General Test Information

INFORMATION ABOUT COMMONLY DONE TESTS IN ALPHABETICAL ORDER

 

 

ABS EOSINOPHIL COUNT, BLOOD

When Absolute Eosinophil Count (AEC) exceeds 400 cells/cumm it is termed as Eosinophilia. AEC is subject to diurnal variation. AEC level is inversely related to blood glucocorticoid levels.

Increased eosinophils are seen most commonly in allergic reactions and parasitic infestations. The other less common causes are lymphoproliferative disorders, collagen disorders, Loeffler's syndrome, rabies and less active phase of malaria.

Test method: Hematology cell analyzer & microscopy


ACT PARTIAL THROMBO PLASTIN TIME (APTT), PLASMA


APTT is a sensitive test, to demonstrate defects in the intrinsic pathway of coagulation. A result which is consistently 7 seconds or more than the normal control [Normal Pool Plasma] should be considered abnormal. Hence, the in range and out of range column should not be considered. Prolonged Results may be seen in heparin therapy, presence of circulating anticoagulant, Hemophilia A and disseminated intravascular coagulation and early liver disease. APTT is used for monitoring unfractionated heparin therapy.

APTT mixing studies -
Poor or partial correction may be obtained in the presence of anticoagulant drugs such as heparin or direct thrombin inhibitors. Total correction indicates coagulation factors deficiency.

Test method: Clotting time based assay


ADENOSINE DEAMINASE
Introduction :

Adenosine deaminase (
ADA) specifically reacts with adenosine and several adenine nucleoside analogues. This enzyme is widely distributed in various tissues of the body. The enzyme level in serum increases in patients with viral hepatitis, infectious mononucleosis, typhoid, liver cirrhosis and in different types of malignant tumors. Increased ADA activity may be found in effusions or body fluids due to tuberculosis, bacterial infections, rheumatologic disease and lymphoproliferative disorders. For biochemical purposes the ADA acitivity can be measured by spectrophotometric method.(1,2).

Principle :

ADA is easily assayed by measuring the amount of ammonia formed during 60 minutes of incubation at 37°C. Ammonia reacts in presence of sodium nitrosyl pentacyanoferrate (III) as a catalyst, with sodium hypochlorite and phenol in alkaline solution, producing a deep blue compound-indophenol. The ammonia concentration is directly proportional to the absorbance of the indophenol at 625 nm(3).

Recommendations :

Stability of
ADA activity in biological specimens varies considereably with respect to time and temperature of storage. Storage of the specimen under frozen conditions until the test is performed is recommended.

Test Technique: Spectrophometry

References:

1. Piras, M., and Gakis, C.: Cerebrospinal Fluid Adenosine Deaminase Activity in Tuberculous Meningitis, Enzyme, 14, 311 (1973).
2. Nishizawa, T., Nishida, Y., Akaoka,
I., and Yoshimura, T.: Erythrocyte Adenosine Deaminase and Purine Nucleoside Phosphorylase Activity in Gout, Clin. Chim. Acta, 58, 277 (1975).
3. Giusti, G. & Galanti, B. Methods of Enzymatic Analysis , Verlag Chemie, Weinheim, p.315, 1984.


AEROBIC CULTURE


Many organisms are associated with infections of skin and subcutaneous tissues. Wound cultures include examination for aerobes and microscopic evaluation for bacteria, yeast cells, fungi and parasites. Clinical information inputs provided, play an important role in assisting the microbiologist to correctly differentiate potential pathogens from normally occurring microorganisms. The final interpretation can be made by the clinician in consultation with the microbiologist on the basis of the clinical status of the patient. Speciation of all isolates recovered after culture of the specimen is carried out using conventional/API systems of identification.

All culture isolates are maintained for a period of 7 days to facilitate additional test, if required.

Test method: Culture and identification


AEROBIC SUSCEPTIBILITY GRAM NEGATIVE ORGANISM
Antimicrobial susceptibility testing is indicated for any isolate contributing to an infectious process warranting antimicrobial chemotherapy, whose susceptibility cannot be reliably predicted from knowledge of its identity, or is thought to belong to a species capable of exhibiting resistance to commonly used antimicrobial agents. Susceptibility testing may also be performed for epidemiological studies of resistance patterns and clinical studies of new antimicrobial agents. The purpose of testing is to identify the drug/s having maximum efficacy against the infecting organism and to minimize the emergence of drug resistance by overuse of broad-spectrum agents.

Method of Testing:
The Microscan® Walkway SI is a rapid automated system for the identification and susceptibility testing of clinically relevant bacteria with a novel panel inoculation system. The antimicrobial susceptibility tests are miniaturization of the broth dilution susceptibility test, which have been dehydrated. After inoculation and rehydration with a standardized suspension of organism and incubation in the Microscan® system at 350C for a minimum of 16 hrs, the minimum inhibitory concentration (MIC) or a qualitative susceptibility (Sensitive, Intermediate or Resistant) for the test organism is determined by observing the lowest antimicrobial concentration showing inhibition of growth. The Microscan® Walkaway SI has inbuilt software that provides test interpretations as per the Clinical & Laboratory Standards Institute (CLSI) standards.

Notes:
• A test interpreted as Sensitive implies that the “Infection due to the isolate may be appropriately treated with the dosage of an antimicrobial agent recommended for that type of infection and infecting species, unless otherwise indicated”
• A test interpreted as Intermediate implies that the “Infection due to the isolate may be appropriately treated in body sites where the drugs are physiologically concentrated or when a high dosage of drug can be used”
• A test interpreted as Resistant implies that the “Isolates are not inhibited by the usually achievable concentrations of the agent with normal dosage schedules and/or fall in the range where specific microbial resistance mechanisms are likely (e.g., beta-lactamases), and clinical efficacy has not been reliable in treatment studies.
• Though the Microscan® Walkaway SI system interprets antimicrobial susceptibility results of most common organisms within 16-20 hours of incubation, detection of resistance may require extended incubation times(24-48 hours) for the certain organisms/ antimicrobials. These include (i) Detection of Vancomycin resistance against Enterococci, (ii) Detection of Oxacillin resistance against Staphylococci and (iii) Detection of High-level aminoglycoside resistance in Enterococci.


AEROBIC SUSCEPTIBILITY GRAM POSITIVE ORGANISM

Antimicrobial susceptibility testing is indicated for any isolate contributing to an infectious process warranting antimicrobial chemotherapy, whose susceptibility cannot be reliably predicted from knowledge of its identity, or is thought to belong to a species capable of exhibiting resistance to commonly used antimicrobial agents. Susceptibility testing may also be performed for epidemiological studies of resistance patterns and clinical studies of new antimicrobial agents. The purpose of testing is to identify the drug/s having maximum efficacy against the infecting organism and to minimize the emergence of drug resistance by overuse of broad-spectrum agents.

Method of Testing:
The Microscan® Walkaway SI is a rapid automated system for the identification and susceptibility testing of clinically relevant bacteria with a novel panel inoculation system. The antimicrobial susceptibility tests are miniaturization of the broth dilution susceptibility test, which have been dehydrated. After inoculation and rehydration with a standardized suspension of organism and incubation in the Microscan® system at 350C for a minimum of 16 hrs, the minimum inhibitory concentration (MIC) or a qualitative susceptibility (Sensitive, Intermediate or Resistant) for the test organism is determined by observing the lowest antimicrobial concentration showing inhibition of growth. The Microscan® Walkaway SI has inbuilt software that provides test interpretations as per the Clinical & Laboratory Standards Institute (CLSI) standards.

Notes:
• A test interpreted as Sensitive implies that the “Infection due to the isolate may be appropriately treated with the dosage of an antimicrobial agent recommended for that type of infection and infecting species, unless otherwise indicated”
• A test interpreted as Intermediate implies that the “Infection due to the isolate may be appropriately treated in body sites where the drugs are physiologically concentrated or when a high dosage of drug can be used”
• A test interpreted as Resistant implies that the “Isolates are not inhibited by the usually achievable concentrations of the agent with normal dosage schedules and/or fall in the range where specific microbial resistance mechanisms are likely (e.g., beta-lactamases), and clinical efficacy has not been reliable in treatment studies.
• Though the Microscan® Walkaway SI system interprets antimicrobial susceptibility results of most common organisms within 16-20 hours of incubation, detection of resistance may require extended incubation times(24-48 hours) for the certain organisms/ antimicrobials. These include (i) Detection of Vancomycin resistance against Enterococci, (ii) Detection of Oxacillin resistance against Staphylococci and (iii) Detection of High-level aminoglycoside resistance in Enterococci.

ALANINE AMINOTRANSFERASE, SERUM

ALT activity is predominantly associated with liver tissue followed by comparatively lower levels in heart, muscles & kidneys. Quantitation of ALT is useful in evaluating liver function.

Test Technique: UV with P5P


ALBERT STAIN
Corynebacterium diptheriae causes diphtheria which is an acute contagious febrile illness. The disease is characterized by a combination of local inflammation with pseudomembrane formation of oropharynx and damage to the heart and peripheral nerves caused by the action of potent antitoxin.

Volutin granules tend to stain more strongly with basic dyes than the rest of the bacterium .They are demonstrated most clearly with Albert’s stain which stains them dark purple but the remainder of the bacterium with a contrasting counter stain .By this method granules stain bluish-black and protoplasm green and other organisms mostly green

Conditions that must be differentiated from diphtheria include streprtococcal pharyngitis,adenovirus ionfection ,infectious mononucleosis and vincent’s disease.



ALBUMIN+GLOBULIN+A/G RATIO, SERUM
Test method: Spectrophotometry


ALBUMIN, SERUM

Test Technique: Bromocresol Purple


ALKALINE PHOSPHATASE (ALP) ISOENZYMES

ALP isoenzyme studies indicate whether the total ALP is increased on the basis of contributions from liver, bone, intestinal and/or placental fractions. The liver fraction is more heat stable whereas the heat labile fraction is mainly contributed by bone. However, for further differentiation of ALP isoenzymes specific alkaline phosphatase electrophoresis is advised.

ALANINE AMINOTRANSFERASE, SERUM

ALT activity is predominantly associated with liver tissue followed by comparatively lower levels in heart, muscles & kidneys. Quantitation of ALT is useful in evaluating liver function.

Test Technique: UV with P5P


ALANINE AMINOTRANSFERASE, SERUM

Method: UV with P5P
Kit used: Dade
Manufacturer: Dade Behring Inc.
New York, DE 19714, USA


ALPHA FETOPROTEIN (TITRE), SERUM

Alpha-FetoProtein is normally synthesized in the liver, yolk sac and gastrointestinal tract of the fetus.

Test method: Chemiluminescence.

ALPHA-FETOPROTEIN, SERUM

Alpha- Feto Protein is normally synthesized in the liver, yolk sac and gastrointestinal tract of the fetus.

Test method: Chemiluminescence

ALPHA-FETOPROTEIN, FLUID

Alpha-Fetoprotein is synthesized primarily in the liver and yolk sac of the fetus.

Please note: The reference range for Alpha-Fetoprotein in Fluids has not been established.

Test method: Chemiluminescence.


AMYLASE, URINE

Concentration of amylase in urine increases in situations in which serum amylase concentration is elevated, urinary amylase concentration remains elevated upto 7 days after amylase levels have returned to normal, following an attack of pancreatitis. Thus, the determination of urinary amylase may be useful if the patient is seen late in course of an attack of pancreatitis. An elevated serum amylase with normal or low urine amylase excretory rate may be seen in presence of renal insufficiency or with macroamylasmia.

Test method: Spectrophotometry


AMYLASE, SERUM

Amylase enzyme is of predominantly pancreatic or salivary gland origin. Amylase levels increase in acute pancreatitis, pseudo- cyst of pancreas, obstruction of pancreatic ducts, mumps, occasionally elevated in renal insufficiency, ruptured ectopic pregnancy, appendicitis, dissecting aortic aneurysm, cerebral trauma, diabetic acidosis and inflammation of pancreas from a perforating peptic ulcer. Rarely, combination of amylase with an immunoglobulin produces elevated serum amylase activity (macro amylasemia) because the large molecular complex is not filtered by the glomerulus.

Decrease in amylase level is seen in acute and chronic hepatitis, pancreatic insufficiency, advanced cystic fibrosis, pancreatectomy and occasionally in toxemia of pregnancy.

Test Technique: Ethylidine PNPG7


HIV- 1&2 ABS (EIA)

Antibodies to HIV-1 & -2 can be detected by Enzyme Immunoassay (EIA) or Western blot (Immunoblot). Western blot is technique for detecting the presence of antibodies to electrophoretically separated viral proteins from HIV. Seroconversion (The appearance of antibodies) is still thought to typically occur within 6 months of infection by HIV. Only sera which give "Positive" results by both EIA and western blot should be considered confirmed Positive for HIV antibodies. Likewise, only sera which give "Not Detected" results by both EIA and western blot should be considered confirmed Negative for HIV antibodies.


RECOMMENDATIONS:

"Intermediate" results for HIV antibodies by western blot are those in which the assay does not permit reliable differentiation of "Positive" from "Not Detected". Such indeterminate results should be followed up with a repeat specimen within three months. An individual repeatedly Positive for HIV by EIA whose HIV western blot results continue to be consistently indeterminate for at least 6 months - in the absence of any known risk factors, clinical symptoms, or any other findings - may be considered to be Negative for antibodies to HIV. Neonates born of HIV infected mothers can have HIV infection or can be uninfected despite the presence of maternal antibodies to HIV in their blood. Such babies should undergo additional testing such as polymerase chain reaction (HIV DNA by PCR: Test No. 9885B) to ascertain their status of infection. All sera are stored frozen for six weeks at SRL Ranbaxy for additional testing.


HEP B SURF AG- EIA

HBS AG appears in the blood about six weeks after infection and disappears by three months. Persistence for more than six months implies a carrier state.The Enzyme Immunoassay for the detection of Hepatitis B surface antigen is a highly sensitive sreening test and can therfore yield false Positive results. The proportion of false reactives will depend on the sensitivity and specificity of the test kit. Hence, it is recommended that a Positive result of HBSAG must be confirmed using a different Enzyme Immunoassay kit or by using a confirmatory assay based on neutralisation with human anti Hepatitis B surface antibody.Based on the clinical history, it may become necessary to test for presence of other markers of Hepatitis B virus infection.


VDRL, Serum:

VDRL detects antibodies found in early syphilis, but can be nonreactive in later stages. Biologic false-Positive are common in a variety of other infections or rheumatic diseases, thus more specific T. Pallidum tests are recommended for confirmation.


************** Methodology: Flocculation (Precipitation) Reaction.


ANTI-PHOSPHOLIPID ANTIBODIES, SERUM


Antibodies against phospholipids, components of the biological membranes, are specific for phospholipids such as Cardiolipin, Phosphatidyl -inositol, -enthanolamine, -serine, -choline and Sphingomyelin. Anti-phospholipid antibodies are frequently found in sera of patients with systemic lupus erythematosus (SLE) and related diseases. The occurrence of anti-phospholipid antibodies in patients with SLE and related diseases is typical for a secondary anti-phospholipid syndrome (APS). In contrast, anti-phospholipid antibodies in patients with no other autoimmune diseases characterize the primary APS. Clinical and experimental evidence have shown a correlation between these auto-antibodies and an enhanced incidence of thrombosis, thrombocytopenia and habitual abortions (as a consequence of placental infarct). Obstetric findings, such as recurrent fetal loss, intrauterine growth retardation and pre-eclampsia may occur in 10-20% of women with APS.

Test method: Enzyme Immuno-Assay.

APOLIPOPROTEIN - A1, SERUM

The A apolipoproteins are the main form of protein found in high density lipoproteins (HDL), although apolipoprotein A-1 is also present in chylomicrons. The main role of apolipoprotein A-1 is the activation of Lecithin cholesterol acyl transferase (LCAT) and removal of free cholesterol from extra-hepatic tissues. Apoliprotein A-1 may therefore be described as non-atherogenic, showing an inverse relationship to cardiovascular risk. Serial studies of apolipoproteins A-1 and B may be useful for monitoring patients on diet / exercise programs.

Decreased level is associated with increased risk of coronary heart disease (CHD). Other conditions associated with decreased levels of apolipoprotein A-1 are familial hypoalphalipoproteinemia, Tangier disease, Diabetes mellitus, Cholestasis, hemodialysis, Infection.

Increased levels found in familial hyperalphalipoproteinemia, pregnancy, estrogen therapy, alcohol consumption, exercise.

Test Technique: Nephelometry


APOLIPOPROTEIN - B, SERUM

The B apolipoproteins are the main form of protein found in low density lipoproteins (LDL). Apo B shows atherogenic signs and is thus useful for the evaluation of coronary risk. Serial studies of apolipoproteins A-1 and B may be useful for monitoring patients on diet / exercise programs.

Elevated levels of apolipoprotein B are more powerful indicators of disease than cholesterol or LDL in angiographic coronary artery disease.

Test Technique: Nephelometry


Protein Fractions

Serum protein electrophoresis separates the proteins into five zones - Albumin, Alpha-1, Alpha -2, Beta and Gamma Globulins. Serum protein electrophoresis is used to screen for various disease conditions. Albumin concentrations diminished in disease affecting vascular permeability. The alpha-1 band is made up of alapha-1 lipoprotein, alpha-1, antitryspin (deficiency is associated with juvenile pulmonary emphysema) and alpha-1 acid glycoprotein (an acute phase reactant). The principal proteins of the alpha-2 band are alpha-2 macroglobulin, haptoglobin and alpha- 2 lipoprotein. Alpha-2 macroglobulin is elevated in nephrotic syndrome and in acute inflammation. The beta fraction consists of beta- lipoproteins, transferrin, plasminnogen and complement components. The gamma regions consists screening tool for multiple myeloma in which one of the immunoglobulins shows a monoclonal increase manifesting as a 'M' band. Antinuclear AB-IFA, Hep2 the presence of one or more circulating serum autoantibodies to nuclear antgens is a hallmark of systemic rheumatic diseases. A Negative ANA test virtually rules out a diagnosis of Systemic Lupus Erythematosus but a Positive test may be indicative of a number of autoimmune connective tissue diseases such as scleroderma, rheumatoid arthritis and sjorgen's syndrome. ANA test carried out by immunofluoresence assay using Hep-2 slide (Tissue Culture Substrate) is more sensitive & specific than ANA carried out by Enzyme Immunoassay. The ANA pattern seen or immunofluorscence staining helps in determination of the antibody specificities which need to be confirmed by immunoblot techniques.

Please refer to the following Test Codes for Specific Antibody Determination:

# 1220 : SM(Smith) Antibody
# 1204 : SS-A Antibody
# 1205 : SS-B Antibody
# 1007 : SS-A & SS-B Antibodies
# 1215 : ULSNRNP Antibody
# 1235 : SCL -70 Antibody
# 1208 : JO-1 Antibody
# 1705 : SS-A, SS-B, SM & ULSNRNP Antibodies.

Antistreptolysin ABS LPA


Concentration of Antistreptolysin O (ASO) antibodies are increased in 80-85% of patients with acute rheumatic fever, and anti-Dnase B antibodies are typically elevated in the remaining 15-20%. The stage of the disease determines the utility of the serological assays. At the time of acute polyarthritis in acute rheumatic fevers, also and anti-Dnase B are usually at their peak. By the time carditis becomes evident the concentrations may already be declining. Also antibody concentrations can be elevated in only about 57% of patients with acute glomerulo nephritis after streptococcal epidermal, whereas anti-Dnase B is elevated in 90% of these patients, making anti-Dnase B the test of choice in this setting. Antihyaluronidase is also useful in diagnosis of post-streptococcal glomerulonephritis. The onsent of chorea is usually months after the antecedent streptococcal infection and although streptococcal antibodies may be elevated at the time of Onset of chorea, they are sometimes not a peak concentration.


RECOMMENDATIONS:

Please call SRL Ranbaxy if testing for other streptococcal antibodies (anti-Dnase or anti-Hyaluronidase) is clinically indicated. Please provide the SRL Rambaxy accession number of this specimen when submitting follow-up specimen. The specimens will be tested simultaneously to optimize the utility of the results. All sera are stored frozen for six weeks for additional testing.

URINALYSIS

*********** Microscopic examination carried out on Centrifuged Urinary Sediment.


PROTEIN FRACTIONS

Serum protein electrophoresis separates the proteins into five zones - Albumin, Alpha-1, Alpha -2, Beta and Gamma globulins. Serum protein electrophoresis is used to screen for various disease conditions. Albumin concentrationis diminished in disease affecting vascular permeability. The Alpha-1 band is made up of Alapha-1 lipoprotein, Alpha-1, antitryspin (deficiency is associated with Juvenile pulomnary emphysema) and alpha-1 acid glycoprotein (an acute phase reactant). The principal proteins of the alpha-2 band are alpha-2 macroglobulin, haptoglobin and alpha- 2 lipoprotein. Alpha-2 macroglobulin is elevated in nephrotic syndrome and in acute inflamation. The beta fraction consists of beta- lipoproteins, transferrin, plasminnogen and complement components. The Gamma regions consists screening tool for multiple myeloma in which one of the Immunoglobulins shows a monoclonal increase manifesting as a 'M' band. Antinuclear AB-IFA, Hep2 the presence of one or more circulating serum autoantibodies to nuclear antigens is a hallmark of systemic rheumatic diseases. A Negative ANA test virtually rules out a diagnosis of Systemic Lupus Erythematosus but a Positive test may be indicative of a number of autoimmune connective tissue diseases such as Scleroderma, Rheumatoid Arthritis and Sjorgen's Syndrome. ANA test carried out by immunofluorsence assay using Hep-2 slide (Tissue Culture Substrate) is more sensitive & specific than ANA carried out by Enzyme Immuno-assay. The ANA pattern seen or immunofluorscence staining helps in determination of the antibody specificities which need to be confirmed by immunoblot techniques.


Please refer to the following Test Codes for Specific Antibody Determination:

# 1220 : SM(Smith) Antibody
# 1204 : SS-A Antibody
# 1205 : SS-B Antibody
# 1007 : SS-A & SS-B Antibodies
# 1215 : U1SNRNP Antibody
# 1235 : SCL -70 Antibody
# 1208 : JO-1 Antibody
# 1705 : SS-A, SS-B, SM & U1SNRNP Antibodies.


Antistreptolysin abs LPA
Concentration of Antistreptolysin O (ASO) antibodies are increased in 80-85% of patients with acute rheumatic fever, and anti-DNASE B antibodies are typically elevated in the remaining 15-20%. The stage of the disease determines the utility of the serological assays. At the time of acute polyarthritis in acute rheumatic fever, also and anti-DNASE B are usually at their peak. By the time carditis becomes evident the concentrations may already be declining. Also antibody concentrations can be elevated in only about 57% of patients with acute glomerulo nephritis after streptococcal pydoerma, whereas anti-DNASE B is elevated in 90% of these patients, making anti-DNASE B the test of choice in this setting. Antihyaluronidase is also useful in diagnosis of post-streptococcal glomerulonephritis. The onsent of chorea is usually months after the antecedent streptococcal infection and although streptococcl antibodies may be elevated at the time of onset of chorea, they are sometimes not a peak cncentration.


RECOMMENDATIONS:

Please call SRL Ranbaxy if testing for other streptococcal antibodies (anti-DNASE or anti-hyaluronidase) is clinically indicated. Please provide the SRL Ranbaxy accession number of this specimen when submitting follow-up specimens. The specimens will be tested simultaneously to optimize the utility of the results. All sera are stored frozen for six weeks for additional testing.


Urinalysis
*********** Microscopic examination carried out on Centrifuged Urinary Sediment.


ASPARTATE AMINOTRANSFERASE, SERUM


Aspartate Aminotransferase (SGOT/ AST) is widely distributed in tissues with highest concentration in liver, heart and skeletal muscle. Acute destruction of these tissue results in release of sizeable amounts of AST in systemic circulation following myocardial infarction, serum AST level begin to rise within 4- 6 hours after the onset of angina, reaching a peak in 24- 36 hours.

Serum AST activity is also high in hepatitis and other forms of liver diseases associated with hepatocellular necrosis, infectious mononucleosis, muscular dystrophy, dermatomyositis and in other forms of muscle and liver injury.

Test Technique: UV with P5P


BETA-THALASSEMIA
Clinical utility:
Beta-thalassemia, Autosomal recessesive disorder is characterized by reduced synthesis of the beta globin chain of Hemoglobin. Beta Globin gene ( HBB) is located on short arm of chromosome 11 and more than 200 HBB gene mutation are known to be associated with Beta Thalassemia.
The distribution of beta thalassemia gene is not uniform in the Indian subcontinent. The highest frequency of beta thalassemia trait is reported in
Gujarat, followed by Sindh, Punjab, Tamil Nadu, South India and Maharashtra. Beta Thalassemia is common among Sindhi, Gujarati, Parsee, Punjabi Hindus, Lohanas and Teli communities of India.
Five common mutation (619 bp deletion, cd 8/9 + G, IVS1-1 G T, IVS1-5 G C, 41/42 - TTCT) accounting for 90 to 95% cases in
India.
The test identifies these five mutations in heterozygous or homozygous state.

Method:
Multiplex Polymerase Chain reaction

Interpretation:
Detection of any of these five mutations in heterozygous form confirms the carrier state for the same Beta thalassemia mutation. Detection of any of these five mutations in homozygous form confirms the Beta thalassemia disease due to the same Beta thalassemia mutation.

Please note that this test is not intended to diagnose Beta Thalassemia status, which should be correlated with clinical and other hematological parameters. The test is intended to identify the common five mutations prevalent in
India and negative result does not rule out the other known mutations.

Limitation:
PCR is a highly sensitive technique; common reasons for paradoxical results are contamination during specimen collection, selection of inappropriate specimens and inherent PCR inhibitors in the specimen.

"This test is developed and validated at SRL Ranbaxy Ltd. Due to limited population specific data, currently this test is meant for research use only".

References:
1. Indian Pediatrics 2001; 38: 530-534.
2. Clinical management of beta-thalassemia major. Semin Hematol 38:350-9.


BETA-THALASSEMIA PND

Clinical utility:
" Beta-thalassemia, Autosomal recessesive disorder is characterized by reduced synthesis of the beta globin chain of Hemoglobin. Beta Globin gene ( HBB) is located on short arm of chromosome 11 and more than 200 HBB gene mutation are known to be associated with Beta Thalassemia.
" The distribution of beta thalassemia gene is not uniform in the Indian subcontinent. The highest frequency of beta thalassemia trait is reported in
Gujarat, followed by Sindh, Punjab, Tamil Nadu, South India and Maharashtra. Beta Thalassemia is common among Sindhi, Gujarati, Parsee, Punjabi Hindus, Lohanas and Teli communities of India.
" Five common mutations (619 bp deletion, cd 8/9 + G, IVS1-1 G T, IVS1-5 G C, 41/42 - TTCT) account for 90 to 95% cases in
India.
" The test identifies these common mutations in parents and correlates the status of the same mutation in the fetus. The VNTR analysis is done to rule out maternal cell contamination.

Method:
VNTR analysis for maternal cell contamination and Multiplex Polymerase Chain reaction for mutation detection

Interpretation:
Detection of any of these five mutations in heterozygous form confirms the carrier state for the same Beta thalassemia mutation.
Detection of any of these five mutations in homozygous form confirms the Beta thalassemia disease due to the same Beta thalassemia mutation.
Please note that this test is not intended to diagnose Beta Thalassemia status, which should be correlated with clinical and other hematological parameters. The test is intended to identify the common five mutations prevalent in
India and negative result does not rule out the other known mutations.
The test results should always be correlated with parental mutation analysis.

Limitation:
PCR is a highly sensitive technique; common reasons for paradoxical results are contamination during specimen collection, selection of inappropriate specimens and inherent PCR inhibitors in the specimen.

"This test is developed and validated at SRL Ranbaxy Ltd. Due to limited population specific data, currently this test is meant for research use only".

References:
1. Indian Pediatrics 2001; 38: 530-534.
2. Clinical management of beta-thalassemia major. Semin Hematol 38:350-9.

BILIRUBIN, INDIRECT, SERUM

Test Technique: Calculation


BILIRUBIN, DIRECT, SERUM

Test Technique: Diazotization


BILIRUBIN, TOTAL, SERUM


Test Technique: Jendrassik Grof


BLOOD UREA NITROGEN, 24HRS URINE

Test method: Spectrophotometry


BLOOD UREA NITROGEN, SERUM

Urea Nitrogen- a metabolic product of protein metabolism- is affected by diet, systemic blood circulation, renal conditions as also post- renal conditions affecting renal function.

Test Technique: Ureas


BREAST MONITOR I, SERUM


CA 15-3

Measurement of CA 15-3 is primarily carried out in women with treated carcinoma of the breast for predicting early recurrence.
Serum CA 15-3 values increase with clinical stage of breast cancer, the highest values occurring in metastatic disease. Serial determinations of CA 15 - 3 are most useful as an indicator of response to therapy.
Being a useful monitoring test, it may be an adjunct for diagnosing certain categories of metastatic breast cancers beyond primary tumors of the breast, particularly in more advanced clinical stages. It may also be used in conjunction with CA 125 and TAG 72 for separation of benign and malignant pelvic masses. It is not suitable as a screening test for breast cancer.

CARCINO-EMBRYONIC ANTIGEN

CEA values are important in diagnosis, status assessment and monitoring in breast and gastrointestinal Carcinomas. CEA should not be used as a screening test for malignancy

Undifferentiated or poorly differentiated tumors do not produce CEA.

Test method: Chemiluminescence.


C-REACTIVE PROTEIN, SERUM


CRP is one of the proteins commonly referred to as acute phase reactants. CRP is distinguished by its rapid response to trauma or infection. Testing for CRP is indicated in the following clinical situations - monitoring recovery from surgery, myocardial infarction, transplantation, inflammatory bowel disease, rheumatic diseases and infectious diseases.

CRP levels in autoimmune diseases may show little or no increase unless infection is present. Levels may not increase in conditions like pregnancy, angina, seizures, asthma, common cold.

Elevated levels of CRP may be seen in inflammatory disorders, tissue injury or necrosis and infections.

Test technique: Immunoturbidimetry

C-REACTIVE PROTEIN, SERUM

C - reactive protein (CRP) is an acute phase reactant protein that has the property of showing elevations in concentrations in response to stressful or inflammatory states that occur with infection, injury, surgery, trauma or other tissue necrosis.

Synthesis of CRP increases within 4-6 hours of onset of inflammation, reaching peak values within 1-2 days. CRP levels also fall quickly after resolution of inflammation since its half life is 6 hours. The main limitation of CRP is in its non-specific response and should not be interpreted without a complete clinical history and evaluation.

Test Technique: Latex Agglutination


C-REACTIVE PROTEIN, SERUM

CRP is one of the proteins commonly referred to as acute phase reactants. CRP is distinguished by its rapid response to trauma or infection. Testing for CRP is indicated in the following clinical situations - monitoring recovery from surgery, myocardial infarction, transplantation, inflammatory bowel disease, rheumatic diseases and infectious diseases.

CRP levels in autoimmune diseases may show little or no increase unless infection is present. Levels may not increase in conditions like pregnancy, angina, seizures, asthma, common cold.

Elevated levels of CRP may be seen in inflammatory disorders, tissue injury or necrosis and infections.

Test technique: Nephelometry


CA 125 (OVARIAN CANCER MONITOR),
SERUM

CA 125 is a surface antigen, identified as a 200-1000 kDa mucin-like glycoprotein associated with non-mucinous epithelial ovarian malignancy. CA 125 is a useful tumor marker for evaluating therapy and monitoring disease status in patients under treatment for ovarian cancer. Measured serially the levels of CA 125 correspond with disease progression or regression. The rate of change in CA 125 is also highly prognostic. As a diagnostic tool however, the level of CA 125 alone is not sufficient to determine the presence or extent of disease. Levels of CA 125 should not be interpreted as absolute evidence of the presence or the absence of malignant diseases. Before treatment, patients with confirmed ovarian carcinoma frequently have levels of CA 125 within the range observed in healthy individuals. Preoperative levels of CA 125 in patients with malignant pelvic masses provide no information regarding the histological grade or diameter of the tumor mass.

Elevated levels of CA 125 can be observed in patients with nonmalignant diseases. Patients with certain benign conditions, such as hepatic cirrhosis, acute pancreatitis, endometriosis, pelvic inflammatory disease, menstruation and first trimester pregnancy show elevated levels of CA 125. Elevated levels are also found in 1 to 2% of healthy donors.
Measurements of CA 125 should always be used in conjunction with other diagnostic procedures, including information from the patient's clinical evaluation. The concentration of CA 125 in a given specimen determined with assays from different manufacturers can vary due to differences in assay methods, calibration, and reagent specificity. Values obtained with different assay methods cannot be used interchangeably. Heterophilic antibodies in human serum can react with reagent immunoglobulins, interfering with in vitro immunoassays. Patients routinely exposed to animals or to animal serum products can be prone to this interference and anomalous values may be observed.

Test method: Chemiluminescence.

The clone for “CA 125" antibody is “OV185:1”.


CA 15-3,
SERUM

CA 15-3 is highly polymorphic glycoprotein belonging to the mucin family and is the product of the MUC-1 gene. CA 15-3 is a circulating tumor marker, which is useful in monitoring the clinical course of breast cancer patients.

Whereas, elevated levels are only present in a small percentage of patients with localized disease, two thirds of the cases with metastatic disease will have significantly elevated levels.

CA 15-3, which can monitor response to therapy and can indicate disease status, is a valuable tool in the management of patients with metastases. It can be used for serial measurements to monitor both the course of disease and response to therapy because of the direct correlation of changing levels of CA 15-3 with clinical status.

In patients with known metastases, a reduction in levels of this marker indicates a good response to treatment, while increasing levels indicate resistance to therapy and progressive disease and justify further clinical evaluation and regular monitoring.

It has also recently been shown that an elevation of CA 15-3 levels above the upper limit of normal in patients with no clinical evidence of disease is an early indicator of recurrence. An elevated serum CA 15-3 level in Stage II or III breast cancer patients in remission provided a positive predictive value of 83.3% for recurrent disease, with an average lead-time of 5.3 months before recurrence was clinically established.

The concentration of CA 15-3 in a given specimen, as determined by assays from different manufacturers, can vary due to differences in assay methods and reagent specificity. Values obtained with different assay method cannot be used interchangeably.

Heterophilic antibodies in human serum can react with reagent immunoglobulins, interfering with in vitro immunoassays. Patients routinely exposed to animals or to animal serum products can be prone to this interference and anomalous values may be observed.

Test method: Chemiluminescence.


CA 19-9,
SERUM

CA 19-9 is tumor-associated antigen that is reactive with an antibody that was produced in response to immunization with a human colon cancer cell line. Although the antibody was derived from a colon cancer line, studies have found assay for CA19-9 more useful in the diagnosis and management of patients with pancreatic rather than colon neoplasia. CA 19-9 has also been shown to be a more sensitive and specific marker of pancreatic cancer than other serologic markers.

Very little of the antigen is found in the blood of normal patients or those with benign disorders, but most patients with pancreatic cancer have elevated levels of CA 19-9. Although elevated levels of CA 19-9 are not distinctively characteristic of pancreatic cancer, it is currently the single most useful blood test in differentiating benign from malignant pancreatic disorders.

A higher diagnostic sensitivity is achieved when an assay for CA 19-9 is combined with imaging analysis, such as ultrasonography or computed tomography (CT). This combination is useful in reaching a diagnosis in patients suspected of having pancreatic cancer despite negative or equivocal results on imaging studies.

The possible success of pancreatic resection and prognosis following surgery may be evaluated using the serum levels of CA 19-9. When used serially, levels of CA 19-9 can predict recurrence of the disease prior to radiographic or clinical findings.

CA 19-9 also detects, in decreasing frequency, bile duct, hepatocellular, gastric, colonic, esophageal and non-gastrointestinal cancer. The specificity of CA 19-9 is limited by its expression in patients with pancreatitis and gastrointestinal diseases.

Serum levels of Ca 19-9 should not be interpreted as absolute evidence of the presence or the absence of malignant disease. Before treatment, patients with confirmed GI carcinoma frequently have levels of CA 19-9 within the range observed in healthy individuals. Additionally elevated levels of CA 19-9 can be observed in patients with non-malignant diseases. Measurement of CA 19-9 should always be used in conjunction with other diagnostic procedures, including information from patient's clinical evaluation.

The concentration of CA 19-9 in a given specimen, as determined by assays from different manufacturers, can vary due to differences in assay methods and reagent specificity. Values obtained with different assay method cannot be used interchangeably.

Heterophilic antibodies in human serum can react with reagent immunoglobulins, interfering with in vitro immunoassays. Patients routinely exposed to animals or to animal serum products can be prone to this interference and anomalous values may be observed.


CALCIUM, 24HR URINE


Ordinarily there is a moderate continuous Urinary Calcium excretion depending upon the intake & diet. In Hyperparathyroidism, the urinary Calcium excretion almost always elevated when Serum Calcium is high.

Test method: Spectrophotometry


CALCIUM, SERUM

Test Technique: O-cresolphthalein complexone


CARCINO EMBRYONIC ANTIGEN, SERUM

Carcinoembryonic antigen (CEA) is a glycoprotein and belongs to a group of tumor markers referred to as oncofetal proteins.

Increased serum CEA levels have been detected in persons with primary colorectal cancer and in patients with other malignancies including gastrointestinal tract, breast, lung, ovarian, prostatic, liver and pancreatic cancers. Elevated serum CEA levels have also been detected in patients with non-malignant disease, especially patients who are older or who are smokers.

CEA levels are not useful in screening the general population for undetected cancers. However, CEA levels provide important information about patient prognosis, recurrence of tumors after surgical removal and effectiveness of therapy.

Serial CEA levels are useful in monitoring the course of disease. CEA levels generally fall to normal or near normal levels within 1 to 4 months after surgical removal of cancerous tissue. A rise in CEA levels may be the first indication of recurrence and may precede physical sings and symptoms. Serial CEA levels are also useful in assessing the effectiveness of therapy or possible metastasis.

CEA is useful tool for monitoring and managing cancer therapy and provides the clinician with additional information about patient prognosis.

The concentration of CEA in a given specimen, as determined by assays from different manufacturers, can vary due to differences in assay methods and reagent specificity. Values obtained with different assay method cannot be used interchangeably.

Heterophilic antibodies in human serum can react with reagent immunoglobulins, interfering with in vitro immunoassays. Patients routinely exposed to animals or to animal serum products can be prone to this interference and anomalous values may be observed.

Test method: Chemiluminescence.


CARCINO EMBRYONIC ANTIGEN


CEA values are important in diagnosis, status assessment and monitoring in breast and gastrointestinal Carcinomas. CEA should not be used as a screening test for malignancy

Undifferentiated or poorly differentiated tumors do not produce CEA.

Note : The reference ranges for CEA in CSF have not been established.

Test method: Chemiluminescence.


CARCINO EMBRYONIC ANTIGEN


CEA values are important in diagnosis, status assessment and monitoring in breast and gastrointestinal Carcinomas. CEA should not be used as a screening test for malignancy

Undifferentiated or poorly differentiated tumors do not produce CEA.

Note : The reference ranges for CEA in CSF have not been established.

Test method: Chemiluminescence.


COMPLETE BLOOD COUNT

Hemoglobin, total leucocyte count and platelate count are stable till 72 hrs. The cell morphology is well preserved for 24hrs. However, between 24 to 72 hrs hrs an increase in MCV and HCT is observed (MCV - 5.0 - 7.5% and HCT - 5.0 - 6.8%) leading to a decrease in MCHC. A direct smear is recommended for an accurate differential WBC count and interpretation of RBC morphology.

TEST TECHINQUE: AUTOMATED HEMATOLOGY ANALYZER AND CORRELATION WITH SMEAR EXAMINATION

Pediatric reference ranges represent amalgamated data from published ranges. {Practical Hematology by Dacie & Lewis (10th Edition)}.

References:
Nathan/Oski, Hematolgy of Infancy and Childhood,3rd Ed,1987.
Practical Hematology by Dacie & Lewis (10th Edition).


CBC-MODIFIED, BLOOD

Test method: Automated hematology analyzer

CHLORIDE, SERUM

Test method: ISE (Ion selective electrodes)


CHOLESTEROL HDL, SERUM

Test Technique: Detergent Methodology


CHOLESTEROL, SERUM

Test Technique: CHOD-POD

COMPLETE BLOOD COUNT

The cell morphology is well preserved for 24hrs. However after 24-48 hrs a progressive increase in MCV and HCT is observed leading to a decrease in MCHC. A direct smear is recommended for an accurate differential count and for examination of RBC morphology.

TEST METHOD: AUTOMATED HEMATOLOGY ANALYZER AND CORRELATION WITH SMEAR EXAMINATION

HEMATOLOGY TEST PERFORMED ON LH 500 INSTRUMENT


COMPLETE BLOOD COUNT:


The cell morphology is well preserved for 24 hrs. However after 48 -72 hrs a mild increase in MCV & PCV is observed leading to a decrease in MCHC. A direct smear is recommended for an accurate differential count and RBC morphology.


COOMB'S TEST, DIRECT, BLOOD

Detects immunoglobulin antibodies and/or complement on patient's membrane. Direct Coomb's test is Positive in hemolytic disease of the new born (ErythroBlastosis Foetalis), auto-immune hemolytic anemia & delayed hemolytic trans-fusion reactions. Weak Positivity is seen in Renal disease, Epithelial Malignancies, Rheumatoid Arthritis’s & Inflammatory Bowel disease. Weakly Positive reactions are not clinically significant. The test performed does not characterize the antibody for its specificity against complement or Immunoglobulin sub-class.

Test method: Tube Agglutination.


CREATINE KINASE (CPK), SERUM

Creatine kinase is primarily found in skeletal muscle, cardiac muscle & brain tissue. Damage to any of these tissues may result in increased CK levels. Cardiac muscle damage following Myocardial Infarction usually results in an increase to 7-12 times the upper limits within 18-30 hours of the infarction. Increased activity is also noted in Hypothyroidism, various types of Muscular Dystrophies, Viral Myositis and similar types of skeletal muscle diseases.

Test Technique: Rosalki, modified


CREATINE KINASE - MB (CK-MB), SERUM

Creatinine kinase are dimeric molecules composed of M and B subunits and exist as isoenzymes MM, MB and BB. 1. CK-MB is distributed primarily in the heart muscle.

Creatinine kinase- MB (CK-MB) test is a sensitive and a specific test to detect myocardial infarction within 24 hours of onset of symptoms. CK-MB is also useful to detect reinfarction or extension of myocardial infarction after 72 hours. It is useful to document and to monitor reperfusion after thrombolytic therapy. Diagnostic value of CK-MB diminishes from
12 to 24 hours, after cardiac sugery. A diagnosis of acute myocardial infarction cannot be made until a period of 12 to 24 hours. 2,3.

In addition to myocardial infarction CK-MB levels are raised in myocardial trauma, myocardial contusion, electrical injury and inflammatory myocarditis. Increases in CK-MB levels are common after angioplasty and may indicate reperfusion.

Declining levels of CK-MB are seen with decrease in muscle mass with advancing of age and in sedentary or bed ridden individuals.

Test Technique: GCKC

REFERENCES:

1. Dawson et al., Biochem. Biophys. Res. Comm 21: 346 (1965)
2. Frances Fischbach. A manual of laboratory and diagnostic tests, Sixth edition: 6:441-444, 2000.
3. Jacques Wallach. Interpretation of Diagnostic tests, seventh edition, 13:643, 2000


CREATININE CLEARANCE

Creatinine clearance is one of the Renal function tests. It is the amount of Creatinine cleared from blood by kidneys per minute. It is a valid measure of Glomerular filtration rate and is useful in following progression of renal disease, to adjust dosages of medications in which renal excretion is pivotal (e.g. Aminoglycosides, methotrexate).

Test method: Spectrophotometry


CREATININE, 24HRS URINE

Test method: Spectrophotometry


CREATININE, SERUM

Creatinine estimation is done to assess kidney function. It is not dependent on dietary factors. Normal values are obtained in kidney diseases, excepting in advanced Renal Failure and therefore its estimation is more valuable if coupled with clearance studies and other Renal Function tests.

Test Technique: Alkaline picrate-kinetic (Jaffe's Kinetic)


C-REACTIVE PROTEIN, SERUM

C - reactive protein (CRP) is an acute phase reactant protein that has the property of showing elevations in concentrations in response to stressful or inflammatory states that occur with infection, injury, surgery, trauma or other tissue necrosis.

Synthesis of CRP increases within 4-6 hours of onset of inflammation, reaching peak values within 1-2 days. CRP levels also fall quickly after resolution of inflammation since its half life is 6 hours. The main limitation of CRP is in its non-specific response and should not be interpreted without a complete clinical history and evaluation.

Test method: Latex particle agglutination


CULTURE; EYE SWAB

The conjunctival sac is relatively free from bacteria due to flushing action of tears and presence of lysozyme. Conjunctivitis is the most common ocular inflammation. The principal causes of acute conjunctivitis are infections, allergens and irritative toxins. Infectious conjunctivitis may cause significant morbidity, depending in part on the type of invading organisms and local ocular defense mechanisms.

In bacterial conjunctivitis, pathogenesis involves exogenous routes of infection with upper respiratory tract infections, hand to eye contact and possible relationship with genital tract infections. Endogenous routes of infection occurs with spread from face and eyelids, lacrimal drainage apparatus and paranasal sinuses

Keratitis or inflammation of the cornea may be produced by infectious organisms or by noninfectious stimuli. Microbial keratitis is a common potentially sight-threatening ocular infection caused by bacteria, fungi, viruses, or parasites and requires prompt management. The causative organisms vary geographically depending on the climate, soil and individual patient factors. However, under appropriate opportunistic conditions, any organism can cause keratitis.

All culture isolates are maintained for a period of 7 days to facilitate additional test, if required.

Test method: Culture and identification


CULTURE; NASOPHARYNGEAL

All culture isolates are maintained for a period of 7 days to facilitate additional test, if required.


CULTURE; SPUTUM
Examination of the sputum remains the mainstay of the evaluation of a patient with lower respiratory tract infection. The most common bacterial agents of acute pneumonia are Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa.

A well-collected sputum specimen, representative of the lower respiratory tract, is necessary for appropriate identifications of pathogens. Unfortunately, expectorated material is frequently contaminated by potentially pathogenic bacteria that colonize the upper respiratory tract (and sometime the lower respiratory tract) without actually causing disease. This contamination reduces the diagnostic specificity of any lower respiratory tract specimen. For this purpose, a Quality (Q) Score is performed on a Gram stained smear to determine the quality of specimen. It involves grading the smear by enumerating the presence of polymorpho neutrophils and squamous epithelial cells. Specimens with Q score of Q1, Q2 & Q3 are considered acceptable for performing culture. A score of Q0 indicates that the specimen is not representative of lower respiratory secretions. Increasing number of epithelial cells accompanied by decreasing numbers of neutrophils indicate salivary contamination. In such situations, a repeat specimen is advised. This is however not true for neutropenic patients.

In circumstances where no clear predominance of a single organism exists on sputum gram stain, the possibility of super infection exists. A more direct method of obtaining lower tract secretions may be necessary.

Test method: Culture and Identification


CULTURE; STOOL - AEROBIC

The Gastrointestinal (GI) tract contains vast, diverse normal flora. The normal flora is an important factor in the response of the host to introduction of a potentially harmful microorganism. It has been shown that whenever reduction in normal flora occurs, because of antibiotic treatment or some host factor, resistance to GI infection is significantly reduced.
Since organisms may be shed intermittently, collection of specimens at different times over several days enhances recovery. The common causative bacterial agents of gastroenteritis are Enterotoxigenic Escherichia coli (ETEC), Enteropathogenic Escherichia coli (EPEC), Vibrio cholerae, Clostridium perfringens, Staphylococcus aureus, Bacillus cereus, Clostridium difficile, Shigella dysenteriae, Salmonella species, Campylobacter species, Shigella species, Vibrio parahaemolyticus, Yersinia enterocolitica and Y.pseudotuberculosis. Gastroenteritis can also caused by viruses, parasites, tuberculosis, Candida albicans, and a variety of other fungi. Laboratory diagnosis involves culturing of stool specimen on to appropriate selective medium in order to inhibit normal flora. The present specimen was processed for Vibrio cholerae, Staphylococcus aureus, Bacillus cereus, Salmonella species, Enteropathogenic Escherichia coli and Shigella species and other Vibrio species.

For further analysis refer test codes # 5702- Yersinia culture, #5704- Campylobacter culture, #5708- Anaerobic culture and #1218- Clostridium difficile culture. All culture isolates are maintained for a period of 15 days to facilitate additional test, if required.

All culture isolates are maintained for a period of 7 days to facilitate additional test, if required.

Test method: Culture and identification


CULTURE; THROAT SWAB

Acute pharyngitis is the most common infection of the upper respiratory tract. Three important causes must be considered: streptococcal, viral, and diphtheritic.

Humans are natural reservoirs of beta-hemolytic Group A streptococci and these organisms are transmitted from person to person by way of the respiratory route. Pharyngitis is the most common infection but is usually self-limited. Upto 25 % of persons may become symptomatic carriers following treatment. Of concern in the management of Group A streptococcal pharyngitis are the nonsusppurative complication like Rheumatic fever and glomerulonephritis. Diphtheria is primarily an infection of children, occurring in sporadic outbreaks. Viral infection, probably the most common cause of acute pharyngitis, is more difficult to differentiate from streptococcal infection. Adenoviruses, Epstein-Barr virus and group A coxsackieviruses are the more common causes of viral pharyngitis.

Interpretation of throat culture results also must take into account the presence of the 'normal' bacterial flora of the oropharynx. The causative pathogens include beta-hemolytic streptococci, Corynebacterium diphtheriae, Bordetella pertusis, Neissseria meningitidis, Haemophilus influenzae, Staphylococcus aureus, Candida albicans, Respiratory viruses, Mycoplasma pneumoniae, N.gonorrhoeae, Chlamydia pneumoniae.

All culture isolates are maintained for a period of 15 days to facilitate additional tests, if required.

Test method: Culture and identification


CULTURE; URINE
Urinary tract infections (UTI) is defined as bacteriuria, that is multiplication of the organisms in urinary tract and the presence of more than 100,000 organisms per mL in mid-stream sample of urine. Pyuria denotes the presence of pus cells in urine, which most often accompanies UTI.

Asymptomatic UTI or ""covert bacteriuria"" can be detected only by urine culture. However in symptomatic patients, a smaller number of bacteria (100 to 10000/mL) may signify infection. In urine specimen obtained by suprapubic aspiration or ""in- and-out"" catheterization and in samples from a patient with an indwelling catheter, colony counts of 100 to 10000/mL generally indicate infection.

Pyuria in the absence of bacteriuria (sterile pyuria) may indicate infection with unusual bacterial agents such as Chlamydia trachomatis, Ureaplasma urealyticum and Mycobacterium tuberculosis or with fungi, in noninfectious urologic condition such as calculi, anatomic abnormality, nephrocalcinosis vesicoureteral reflux, interstitial nephritis, or polycystic disease.
False negative culture may be due to use of antimicrobial agents, total obstruction below the infection, infection with a fastidious organism, renal tuberculosis and diuresis.

Pus cell, Epithelial cells and RBC counts are based on direct uncentrifuged mount and not from the centrifuge sediment. A urine sample collection in Boric acid stabilizer has an advantage of preventing unwanted growth due to its bacteriostatic action against Bacteria, Fungi in urine.

All culture isolates are maintained for a period of 7 days to facilitate additional test, if required.

Test method: Culture and Identification


CYTOMEGALOVIRUS DNA PCR
Clinical Utility :
--CMV DNA PCR is useful for rapid diagnosis of cytomegalovirus infection, especially in congenitally infected neonates, bone marrow or solid organ transplant recipients, immunocompetent individuals with active infection and healthy blood donors.
--Evidence of CMV viremia in transplant patients helps initiation of preemptive therapy and reduces the risk of chronic graft failure, secondary immune deficiency subsequent to bacterial or fungal infection.
--CMV viremia is intermittent and thus serial sampling is required for optimal detection.

Method :
DNA Polymerase Chain Reaction.

Interpretation :
Detection of target specific band indicates presence of CMV in the given specimen.
No target specific amplification indicates absence of CMV in the given specimen.

All the results should always be correlated with clinical status and history of the patient.

Limitations :
PCR is a highly sensitive technique; common reasons for paradoxical results are contamination during specimen collection, selection of inappropriate specimens and inherent PCR inhibitors in the specimen.

Cytomegalovirus (CMV) is a member of the Herpesviridae family and is classified as Human herpesvirus Type 5.CMV causes a number of protean disease syndromes in infants as well as adults. Infection is common and reaches most of the population, whereas associated disease is relatively rare. CMV is a recognized cause of mononucleosis and hepatitis amongst normal immunocompetent individuals .But it is among the immunosuppressed (immature neonates, organ transplant recipients, AIDS patients) that CMV causes most significant disease, manifesting as hepatitis, retinitis, pneumonitis, encephalitis, colitis etc.

The risk of an infected pregnant woman transmitting CMV to the foetus is highest in the 3rd trimester and during the birth process (Perinatal infection). Intrauterine/Congenital CMV infections, though less frequently seen than perinatal infections, are responsible for causing severe CMV diseases that may be fatal. Such intrauterine/congenital CMV infections are usually seen in infants born to mothers suffering from a primary infection during pregnancy.

A positive CMV IgM result may not always indicate a primary acute infection, as IgM has a tendency to persist, even at high levels, after primary infection. False-positive IgM results may occur due to rheumatoid factor and antinuclear antibodies. Hence, IgG avidity testing is recommended to differentiate between primary infection, IgM persistence and reactivation.

Avidity is defined as the functional binding strength of antibodies to multiple binding sites (epitopes) on the antigen. The test is based on the principle that antibodies formed in response to primary infection have relatively low avidity to the corresponding antigen. With time, a broader antibody response develops with antibodies being formed to more epitopes on the antigen and with a corresponding increase in the antibody antigen avidity. Therefore, when a secondary antibody response occurs with reinfection, it stimulates clonal expansion of memory B cells to a much wider spectrum of epitopes, producing antibodies of considerably greater avidity.

A positive IgM accompanied by low-avidity IgG is suggestive of a primary infection, whereas a high-avidity IgG indicates either IgM persistence or reactivation. A low avidity index may also be seen in a proportion of infected persons for months. Hence it is advised to perform IgM testing initially to point to the need for IgG avidity to avoid misinterpretation of results.

Test method: Enzyme Immuno-Assay


CYTOMEGALOVIRUS ANTIBODIES, SERUM

The immune response to hCMV involves synthesis of antibodies of the IgM class some weeks after infection by hCMV and, one week later, of antibodies of the IgG class. Levels of IgM to hCMV usually increase for some weeks and decrease slowly thereafter, in four to six months. Occasionally, IgM may circulate for years. Specific IgM assay is instrumental in diagnosing acute hCMV infection, which remains difficult to identify from symptoms alone. However, it is not always possible to distinguish between primary and secondary infection, because reactivation may induce synthesis of IgM in immunocompromized patients. For that reason, the detection of IgM antibodies to CMV should be associated with the study of specific IgG seroconversion by testing paired samples taken at 2-3 weeks interval. A rise in the concentration of anti-CMV specific IgG by a factor of 4 or more in paired samples taken at 3-4 weeks interval tested at the same time in adjacent wells may be indicative of recent infection. Specific IgG assay is useful in distinguishing subjects who have acquired the disease from those who have not. This is particularly important in order to adopt suitable prophylaxis in susceptible individuals.

On account of the diversity or absence of symptoms, the detection of hCMV infection has to be based not on clinical findings, but on serology. However, the conventional single-serum assays do not make a clear distinction between a recent and past infection. In addition, the presence of detectable IgM is generally associated with recently acquired infection, but the persistence of production of these immunoglobulins is variable and can be prolonged. In particular, positive IgM results are not easy to interpret, because specific IgM has a tendency to persist, even at high levels, after primary infection. One solution for the identification of primary infection as opposed to reactivation, chronic infection, IgM persistence or polyclonal response of the immune system may be the measurement of antigen-binding avidity of specific IgG. In fact, the strength of the interaction between antibody in a serum specimen and individual epitopes of a multivalent antigen (i.e., antigen-binding avidity) increases with the duration of infection: low-avidity specific IgG is a strong indicator of recent primary infection in a single serum sample. Positive IgM and low-avidity IgG results are suggestive of primary infection, whereas the finding of high-avidity IgG indicates presence of IgM due to persistence or reactivation. A low avidity index, however, does not indicate for sure a recent infection, as a proportion of infected persons may exhibit persistence of low-avidity IgG antibodies for months. To avoid misinterpretation of positive, yet low IgM response in primary infection, the IgM test will point to the need for IgG avidity determination to overrule primary infection.

Detection of IgM to hCMV allows adequate treatment to be administered, as needed. Prophylaxis of hCMV infection may be achieved by administration of high-titer virus-specific immunoglobulin preparations. In addition, overt disease may be treated with specific antiviral agents.

Test method: Enzyme Immuno-Assay.


CYTOMEGALOVIRUS IgG, SERUM

The immune response to hCMV involves synthesis of antibodies of the IgM class some weeks after infection by hCMV and, one week later, of antibodies of the IgG class. Levels of IgM to hCMV usually increase for some weeks and decrease slowly thereafter, in four to six months. Occasionally, IgM may circulate for years. Specific IgM assay is instrumental in diagnosing acute hCMV infection, which remains difficult to identify from symptoms alone. However, it is not always possible to distinguish between primary and secondary infection, because reactivation may induce synthesis of IgM in immunocompromized patients. For that reason, the detection of IgM antibodies to CMV should be associated with the study of specific IgG seroconversion by testing paired samples taken at 2-3 weeks interval. A rise in the concentration of anti-CMV specific IgG by a factor of 4 or more in paired samples taken at 3-4 weeks interval tested at the same time in adjacent wells may be indicative of recent infection. Specific IgG assay is useful in distinguishing subjects who have acquired the disease from those who have not. This is particularly important in order to adopt suitable prophylaxis in susceptible individuals.

On account of the diversity or absence of symptoms, the detection of hCMV infection has to be based not on clinical findings, but on serology. However, the conventional single-serum assays do not make a clear distinction between a recent and past infection. In addition, the presence of detectable IgM is generally associated with recently acquired infection, but the persistence of production of these immunoglobulins is variable and can be prolonged. In particular, positive IgM results are not easy to interpret, because specific IgM has a tendency to persist, even at high levels, after primary infection. One solution for the identification of primary infection as opposed to reactivation, chronic infection, IgM persistence or polyclonal response of the immune system may be the measurement of antigen-binding avidity of specific IgG. In fact, the strength of the interaction between antibody in a serum specimen and individual epitopes of a multivalent antigen (i.e., antigen-binding avidity) increases with the duration of infection: low-avidity specific IgG is a strong indicator of recent primary infection in a single serum sample. Positive IgM and low-avidity IgG results are suggestive of primary infection, whereas the finding of high-avidity IgG indicates presence of IgM due to persistence or reactivation. A low avidity index, however, does not indicate for sure a recent infection, as a proportion of infected persons may exhibit persistence of low-avidity IgG antibodies for months. To avoid misinterpretation of positive, yet low IgM response in primary infection, the IgM test will point to the need for IgG avidity determination to overrule primary infection.

Detection of IgM to hCMV allows adequate treatment to be administered, as needed. Prophylaxis of hCMV infection may be achieved by administration of high-titer virus-specific immunoglobulin preparations. In addition, overt disease may be treated with specific antiviral agents.

Test method: Enzyme Immuno-Assay.

CYTOMEGALOVIRUS ANTIBODIES, SERUM

The immune response to hCMV involves synthesis of antibodies of the IgM class some weeks after infection by hCMV and, one week later, of antibodies of the IgG class. Levels of IgM to hCMV usually increase for some weeks and decrease slowly thereafter, in four to six months. Occasionally, IgM may circulate for years. Specific IgM assay is instrumental in diagnosing acute hCMV infection, which remains difficult to identify from symptoms alone. However, it is not always possible to distinguish between primary and secondary infection, because reactivation may induce synthesis of IgM in immunocompromized patients. For that reason, the detection of IgM antibodies to CMV should be associated with the study of specific IgG seroconversion by testing paired samples taken at 2-3 weeks interval. A rise in the concentration of anti-CMV specific IgG by a factor of 4 or more in paired samples taken at 3-4 weeks interval tested at the same time in adjacent wells may be indicative of recent infection. Specific IgG assay is useful in distinguishing subjects who have acquired the disease from those who have not. This is particularly important in order to adopt suitable prophylaxis in susceptible individuals.

On account of the diversity or absence of symptoms, the detection of hCMV infection has to be based not on clinical findings, but on serology. However, the conventional single-serum assays do not make a clear distinction between a recent and past infection. In addition, the presence of detectable IgM is generally associated with recently acquired infection, but the persistence of production of these immunoglobulins is variable and can be prolonged. In particular, positive IgM results are not easy to interpret, because specific IgM has a tendency to persist, even at high levels, after primary infection. One solution for the identification of primary infection as opposed to reactivation, chronic infection, IgM persistence or polyclonal response of the immune system may be the measurement of antigen-binding avidity of specific IgG. In fact, the strength of the interaction between antibody in a serum specimen and individual epitopes of a multivalent antigen (i.e., antigen-binding avidity) increases with the duration of infection: low-avidity specific IgG is a strong indicator of recent primary infection in a single serum sample. Positive IgM and low-avidity IgG results are suggestive of primary infection, whereas the finding of high-avidity IgG indicates presence of IgM due to persistence or reactivation. A low avidity index, however, does not indicate for sure a recent infection, as a proportion of infected persons may exhibit persistence of low-avidity IgG antibodies for months. To avoid misinterpretation of positive, yet low IgM response in primary infection, the IgM test will point to the need for IgG avidity determination to overrule primary infection.

Detection of IgM to hCMV allows adequate treatment to be administered, as needed. Prophylaxis of hCMV infection may be achieved by administration of high-titer virus-specific immunoglobulin preparations. In addition, overt disease may be treated with specific antiviral agents.

Test method: Enzyme Immuno-Assay.

COAGULATION


D-DIMER, PLASMA

The level of D-dimer rises during the coagulation activation states. It is a proteolytic product of cross-linked fibrinogen. Increased levels of D-dimer have been reported in the following cases: deep vein thrombosis (DVT), embolisms, DIC, hemorrhages, surgery, cancers and cirrhosis of liver. The D-dimer level generally rises in the first 2 to 3 days post-operatively, and this is an evidence of the fibrinolytic activity directed against the enhanced levels of fibrin produced as a result of surgery. Thus, a high D-dimer level is expected immediately after surgery. If the elevated D-dimer level persists, or tends to rise further, then this is a warning sign of an impending or an ongoing thromboembolic episode.

Disclaimer: However, this test should not be used to exclude deep vein thrombosis (DVT) or pulmonary embolism.

Test method: Latex agglutination slide test.


Dengue Duo Antigen and Antibody Test

Dengue fever is a viral disease transmitted by mosquitoes and caused by four serotypes of dengue virus (DEN): DEN-1, DEN-2, DEN-3, and DEN-4. These viruses cause a wide range of symptoms, from unapparent or mild disease (dengue fever) to a severe hemorrhagic form (dengue hemorrhagic fever). Rapid screening of Dengue infections is currently done using serological tests for Dengue IgG and IgM antibodies. However since IgM antibodies are detectable only after 3-4 days of fever they are not very suitable for diagnosis of early phase of infection. NS1 is a highly conserved glycoprotein that seems to be essential for virus viability but has no established biological activity. It has been demonstrated that the NS1 antigen is present at high concentrations in the sera of dengue virus-infected patients during the early clinical phase of the disease.

Clinical Utility
•NS1 Antigen test allows for early detection of dengue fever infection prior to seroconversion.
•It can be detected in serum from day 1 after onset of clinical signs, up to day 9.
•In combined with rapid IgG and IgM antibodies, this assay provides a sensitive option for screening of early dengue infections.

Method
ELISA

Interpretation
Dengue NS1 antigen is detected in patient serum during early phase of infection i.e. between 1-9 days after onset of clinical signs. Primary dengue infection is characterized by the presence of significant or rising level of IgM along with NS1 Antigen. Levels of NS1 antigen may diminish after 9 days of onset of clinical signs, but IgM can persists for 3-5 months. During Secondary dengue infection, both IgG and IgM are detectable whereas NS1 antigen levels may be not detectable. Detection of NS1 antigen is a marker of acute active infection only because IgM does not become detectable until 5 to 10 days after the onset of illness in case of primary dengue virus infection and until 4 to 5 days after the onset of illness in secondary infections. Once antiNS1 IgG antibodies are produced (generally corresponding to defervescence) NS1 is no longer detectable in the serum

Limitations :
Diagnosis of Dengue fever should not be established on the basis of a single serological test. A precise diagnosis should take into consideration clinical history, symptomatology as well as other serological data

Dengue NS1 Antigen + Antibodies IgG and IgM

Dengue fever is a viral disease transmitted by mosquitoes and caused by four serotypes of dengue virus (DEN): DEN-1, DEN-2, DEN-3, and DEN-4. These viruses cause a wide range of symptoms, from unapparent or mild disease (dengue fever) to a severe hemorrhagic form (dengue hemorrhagic fever). Rapid screening of Dengue infections is currently done using serological tests for Dengue IgG and IgM antibodies. However, since IgM antibodies are detectable only after 5-10 days in case of primary Dengue infection and 4-5 days after the onset of illness in secondary infection. Hence, antibody detection is not very suitable for diagnosis of early phase of infection.
It has been demonstrated that the NS1 antigen is present at high concentrations in the sera of dengue virus-infected patients during the early clinical phase of the disease. Combined detection of NSI antigen, IgG and IgM antibodies in single step helps for early and differential diagnosis of primary and secondary dengue infection.

Clinical Utility
•NS1 Antigen test allows for rapid and early detection of dengue fever infection prior to seroconversion. It can be detected in serum from day 1 after onset of clinical signs, up to day 9.
•In combination with IgG and IgM antibodies, this assay provides a sensitive option for screening of primary and secondary dengue infections.

Method
Rapid Immunochromatographic method

Limitations :
Diagnosis of Dengue fever should not be established on the basis of a single serological test. A precise diagnosis should take into consideration clinical history, symptomatology as well as other serological data.

Reference:
1.J. Clin. Microbiol.2002 40:376–381.
2.J. Clin. Microbiol 2000. 38: 1053–1057.
3.Clin. Infect. Dis.2006. 42:1127–1134.

Dengue NS1 Antigen

Dengue fever is a viral disease transmitted by mosquitoes and caused by four serotypes of dengue virus (DEN): DEN-1, DEN-2, DEN-3, and DEN-4. These viruses cause a wide range of symptoms, from unapparent or mild disease (dengue fever) to a severe hemorrhagic form (dengue hemorrhagic fever). Rapid screening of Dengue infections is currently done using serological tests for Dengue IgG and IgM antibodies. However, since IgM antibodies are detectable only after 5-10 days in case of primary Dengue infection and 4-5 days after the onset of illness in secondary infection. Hence, antibody detection is not very suitable for diagnosis of early phase of infection.

It has been demonstrated that the NS1 antigen is present at high concentrations in the sera of dengue virus-infected patients during the early clinical phase of the disease. Combined detection of NSI antigen, IgG and IgM antibodies in single step helps for early and differential diagnosis of primary and secondary dengue infection.

Clinical Utility

• NS1 Antigen test allows for rapid and early detection of dengue fever infection prior to seroconversion. It can be detected in serum from day 1 after onset of clinical signs, up to day 9.
• In combination with IgG and IgM antibodies, this assay provides a sensitive option for screening of primary and secondary dengue infections.

Method

Dengue NS1 antigen capture ELISA

Limitations :
Diagnosis of Dengue fever should not be established on the basis of a single serological test. A precise diagnosis should take into consideration clinical history, symptomatology as well as other serological data.

Reference:
1.J. Clin. Microbiol.2002 40:376–381.
2.J. Clin. Microbiol 2000. 38: 1053–1057.
3.Clin. Infect. Dis.2006. 42:1127–1134.

Dengue NS1 Antigen

Dengue fever is a viral disease transmitted by mosquitoes and caused by four serotypes of dengue virus (DEN): DEN-1, DEN-2, DEN-3, and DEN-4. These viruses cause a wide range of symptoms, from unapparent or mild disease (dengue fever) to a severe hemorrhagic form (dengue hemorrhagic fever). Rapid screening of Dengue infections is currently done using serological tests for Dengue IgG and IgM antibodies. However, since IgM antibodies are detectable only after 5-10 days in case of primary Dengue infection and 4-5 days after the onset of illness in secondary infection. Hence, antibody detection is not very suitable for diagnosis of early phase of infection.

It has been demonstrated that the NS1 antigen is present at high concentrations in the sera of dengue virus-infected patients during the early clinical phase of the disease. Combined detection of NSI antigen, IgG and IgM antibodies in single step helps for early and differential diagnosis of primary and secondary dengue infection.

Clinical Utility

• NS1 Antigen test allows for rapid and early detection of dengue fever infection prior to seroconversion. It can be detected in serum from day 1 after onset of clinical signs, up to day 9.
• In combination with IgG and IgM antibodies, this assay provides a sensitive option for screening of primary and secondary dengue infections.

Method

Dengue NS1 antigen capture ELISA

Limitations :
Diagnosis of Dengue fever should not be established on the basis of a single serological test. A precise diagnosis should take into consideration clinical history, symptomatology as well as other serological data.

Reference:
1.J. Clin. Microbiol.2002 40:376–381.
2.J. Clin. Microbiol 2000. 38: 1053–1057.
3.Clin. Infect. Dis.2006. 42:1127–1134.


DENGUE RNA PCR

Clinical Utility:
The test is designed to diagnose all four serotypes of Dengue Virus.
PCR is highly sensitive and rapid test which enables the early detection in suspected cases.
Routine diagnostic test like ELISA is useful only after development of immune response.
Detection of Dengue virus by haemagglutination inhibition test (HI), complement fixation (CF), neutralization test and ELISA is susceptible to cross-reactions with other Flaviviruses.

Interpretation:
Detection of specific amplification band indicates presence of Dengue virus RNA in the given sample.
No target specific amplification indicates absence of Dengue RNA in the given sample.
All the results should always be correlated with clinical status and history of the patient.

Negative result could occur due to:
--Very low viral load
--Clearance of Dengue virus

Limitations:
PCR is a highly sensitive technique; common reasons for paradoxical results are contamination during specimen collection, selection of inappropriate specimens and inherent PCR inhibitors in the specimen.

Test technique: Reverse Transcriptase - Polymerase Chain Reaction

References:
1. Dengue Bulletin, 2002, vol 26, p. 125-130.
2. Journal of Clinical Microbiology, Dec'2002, p. 4472-4478.


DENGUE VIRUS ANTIBODIES

Dengue virus, found largely in the tropics and subtropics, is transmitted by mosquitoes, principally aedes aegypti and aedes albopictus, It belongs to the genus Flavivirus and has four serotypes, DEN-1, DEN-2, DEN-3, and DEN-4. Infection with one dengue serotype provides lifelong immunity to that virus, but no cross protective immunity to the other serotypes. World health organization criteria also classify dengue infections as primary or secondary. It is believed that patients experiencing a secondary infection with heterologous serotypes have higher risk of complications, including Dengue Haemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS).
Human dengue infection causes a spectrum of illnesses ranging from inapparent or mild febrile illness to severe to fatal hemorrhagic disease. Infection with any of the four serotypes causes similar disease that may vary in severity,depending on proportion of patients having severe disease during epidemic transmission, strain and serotype of the infecting virus and the immune status, age, and genetic background of the human host.
Classic dengue fever, primarily a disease of older children and adults, is characterized by the sudden onset fever and a variety of nonspecific signs and symptoms, including frontal headache, retro-orbital pain, body aches, nausea and vomiting, joint pains, weakness, and rash. Laboratory findings include neutropenia followed by lymphocytosis and elevated liver enzymes. Dengue fever is generally self-limiting and is rarely fatal. The acute phase of illness lasts for 3 to 7 days, but the convalescent phase may be prolonged for weeks and may be associated with weakness and depression, especially in adults.
DHF is primarily a disease of children under the age of 15 years, although it does occur in adults. It is characterized by sudden onset of fever, lasting for 2 to 7 days .Signs of circulatory failure (DSS) or hemorrhagic manifestations may occur from about 24 h before to 24 h after the temperature falls to normal or below. Blood tests usually show, leucopenia, thrombocytopenia (platelet count, #100,000/mm3) and hemoconcentration .
Dengue specific IgM can be detected as early as 3-5 days after the onset of fever and generally persists for 30-90 days, although detectable levels may be present rarely upto 8 months post-infection. IgM antibody is also produced in secondary and tertiary dengue infections, although the response in some secondary and probably most tertiary infections is low level and transient. Patients with primary dengue infections usually are IgM positive & IgG negative with higher IgM concentrations , whereas patients with secondary infections are usually both IgG and IgM Dengue Shock Syndrome positive with higher IgG concentrations.
Positive results obtained with single serum samples are only provisional and do not necessarily indicate current dengue infection, but point to an infection in the previous 2 to 3 months. Similarly, a negative result with an acute-phase sample may be false-negative if the sample was taken before detectable IgM appeared. Hence accurate serologic diagnosis depends on demonstration of significant (fourfold or greater) rise in antibody titer between acute- and convalescent-phase serum samples.
All flaviviruses (Tick-borne encephalitis virus, Japanese encephalitis virus, Dengue virus) have common group epitopes on the envelope protein that result in extensive crossreactions in serologic tests. Hence patients suffering from other flavivirus infections may give a false positive dengue test.
Differential diagnoses during the acute phase of illness should include measles, rubella, influenza, typhoid, leptospirosis, malaria, other viral hemorrhagic fevers, and any other disease that may present as a nonspecific viral syndrome.


DENGUE VIRUS IgG, SERUM

Dengue virus, found largely in the tropics and subtropics, is transmitted by mosquitoes, principally aedes aegypti and aedes albopictus, It belongs to the genus Flavivirus and has four serotypes, DEN-1, DEN-2, DEN-3, and DEN-4. Infection with one dengue serotype provides lifelong immunity to that virus, but no cross protective immunity to the other serotypes. World health organization criteria also classify dengue infections as primary or secondary. It is believed that patients experiencing a secondary infection with heterologous serotypes have higher risk of complications, including Dengue Haemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS).
Human dengue infection causes a spectrum of illnesses ranging from inapparent or mild febrile illness to severe to fatal hemorrhagic disease. Infection with any of the four serotypes causes similar disease that may vary in severity,depending on proportion of patients having severe disease during epidemic transmission, strain and serotype of the infecting virus and the immune status, age, and genetic background of the human host.
Classic dengue fever, primarily a disease of older children and adults, is characterized by the sudden onset fever and a variety of nonspecific signs and symptoms, including frontal headache, retro-orbital pain, body aches, nausea and vomiting, joint pains, weakness, and rash. Laboratory findings include neutropenia followed by lymphocytosis and elevated liver enzymes. Dengue fever is generally self-limiting and is rarely fatal. The acute phase of illness lasts for 3 to 7 days, but the convalescent phase may be prolonged for weeks and may be associated with weakness and depression, especially in adults.
DHF is primarily a disease of children under the age of 15 years, although it does occur in adults. It is characterized by sudden onset of fever, lasting for 2 to 7 days .Signs of circulatory failure (DSS) or hemorrhagic manifestations may occur from about 24 h before to 24 h after the temperature falls to normal or below. Blood tests usually show, leucopenia, thrombocytopenia (platelet count, #100,000/mm3) and hemoconcentration .
Dengue specific IgM can be detected as early as 3-5 days after the onset of fever and generally persists for 30-90 days, although detectable levels may be present rarely upto 8 months post-infection. IgM antibody is also produced in secondary and tertiary dengue infections, although the response in some secondary and probably most tertiary infections is low level and transient. Patients with primary dengue infections usually are IgM positive & IgG negative with higher IgM concentrations , whereas patients with secondary infections are usually both IgG and IgM Dengue Shock Syndrome positive with higher IgG concentrations.
Positive results obtained with single serum samples are only provisional and do not necessarily indicate current dengue infection, but point to an infection in the previous 2 to 3 months. Similarly, a negative result with an acute-phase sample may be false-negative if the sample was taken before detectable IgM appeared. Hence accurate serologic diagnosis depends on demonstration of significant (fourfold or greater) rise in antibody titer between acute- and convalescent-phase serum samples.
All flaviviruses (Tick-borne encephalitis virus, Japanese encephalitis virus, Dengue virus) have common group epitopes on the envelope protein that result in extensive crossreactions in serologic tests. Hence patients suffering from other flavivirus infections may give a false positive dengue test.
Differential diagnoses during the acute phase of illness should include measles, rubella, influenza, typhoid, leptospirosis, malaria, other viral hemorrhagic fevers, and any other disease that may present as a nonspecific viral syndrome.

Test technique: Enzyme Immunoassay


DENGUE VIRUS IgG, SERUM

Dengue virus, found largely in the tropics and subtropics, is transmitted by mosquitoes, principally aedes aegypti and aedes albopictus, It belongs to the genus Flavivirus and has four serotypes, DEN-1, DEN-2, DEN-3, and DEN-4. Infection with one dengue serotype provides lifelong immunity to that virus, but no cross protective immunity to the other serotypes. World health organization criteria also classify dengue infections as primary or secondary. It is believed that patients experiencing a secondary infection with heterologous serotypes have higher risk of complications, including Dengue Haemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS).
Human dengue infection causes a spectrum of illnesses ranging from inapparent or mild febrile illness to severe to fatal hemorrhagic disease. Infection with any of the four serotypes causes similar disease that may vary in severity,depending on proportion of patients having severe disease during epidemic transmission, strain and serotype of the infecting virus and the immune status, age, and genetic background of the human host.
Classic dengue fever, primarily a disease of older children and adults, is characterized by the sudden onset fever and a variety of nonspecific signs and symptoms, including frontal headache, retro-orbital pain, body aches, nausea and vomiting, joint pains, weakness, and rash. Laboratory findings include neutropenia followed by lymphocytosis and elevated liver enzymes. Dengue fever is generally self-limiting and is rarely fatal. The acute phase of illness lasts for 3 to 7 days, but the convalescent phase may be prolonged for weeks and may be associated with weakness and depression, especially in adults.
DHF is primarily a disease of children under the age of 15 years, although it does occur in adults. It is characterized by sudden onset of fever, lasting for 2 to 7 days .Signs of circulatory failure (DSS) or hemorrhagic manifestations may occur from about 24 h before to 24 h after the temperature falls to normal or below. Blood tests usually show, leucopenia, thrombocytopenia (platelet count, #100,000/mm3) and hemoconcentration .
Dengue specific IgM can be detected as early as 3-5 days after the onset of fever and generally persists for 30-90 days, although detectable levels may be present rarely upto 8 months post-infection. IgM antibody is also produced in secondary and tertiary dengue infections, although the response in some secondary and probably most tertiary infections is low level and transient. Patients with primary dengue infections usually are IgM positive & IgG negative with higher IgM concentrations , whereas patients with secondary infections are usually both IgG and IgM Dengue Shock Syndrome positive with higher IgG concentrations.
Positive results obtained with single serum samples are only provisional and do not necessarily indicate current dengue infection, but point to an infection in the previous 2 to 3 months. Similarly, a negative result with an acute-phase sample may be false-negative if the sample was taken before detectable IgM appeared. Hence accurate serologic diagnosis depends on demonstration of significant (fourfold or greater) rise in antibody titer between acute- and convalescent-phase serum samples.
All flaviviruses (Tick-borne encephalitis virus, Japanese encephalitis virus, Dengue virus) have common group epitopes on the envelope protein that result in extensive crossreactions in serologic tests. Hence patients suffering from other flavivirus infections may give a false positive dengue test.
Differential diagnoses during the acute phase of illness should include measles, rubella, influenza, typhoid, leptospirosis, malaria, other viral hemorrhagic fevers, and any other disease that may present as a nonspecific viral syndrome.

Test technique: Enzyme Immunoassay


DENGUE VIRUS IgM, SERUM


Dengue virus, found largely in the tropics and subtropics, is transmitted by mosquitoes, principally aedes aegypti and aedes albopictus, It belongs to the genus Flavivirus and has four serotypes, DEN-1, DEN-2, DEN-3, and DEN-4. Infection with one dengue serotype provides lifelong immunity to that virus, but no cross protective immunity to the other serotypes. World health organization criteria also classify dengue infections as primary or secondary. It is believed that patients experiencing a secondary infection with heterologous serotypes have higher risk of complications, including Dengue Haemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS).
Human dengue infection causes a spectrum of illnesses ranging from inapparent or mild febrile illness to severe to fatal hemorrhagic disease. Infection with any of the four serotypes causes similar disease that may vary in severity,depending on proportion of patients having severe disease during epidemic transmission, strain and serotype of the infecting virus and the immune status, age, and genetic background of the human host.
Classic dengue fever, primarily a disease of older children and adults, is characterized by the sudden onset fever and a variety of nonspecific signs and symptoms, including frontal headache, retro-orbital pain, body aches, nausea and vomiting, joint pains, weakness, and rash. Laboratory findings include neutropenia followed by lymphocytosis and elevated liver enzymes. Dengue fever is generally self-limiting and is rarely fatal. The acute phase of illness lasts for 3 to 7 days, but the convalescent phase may be prolonged for weeks and may be associated with weakness and depression, especially in adults.
DHF is primarily a disease of children under the age of 15 years, although it does occur in adults. It is characterized by sudden onset of fever, lasting for 2 to 7 days .Signs of circulatory failure (DSS) or hemorrhagic manifestations may occur from about 24 h before to 24 h after the temperature falls to normal or below. Blood tests usually show leucopenia, thrombocytopenia (platelet count, #100,000 /mm3) and hemoconcentration .
Dengue specific IgM can be detected as early as 3-5 days after the onset of fever and generally persists for 30-90 days, although detectable levels may be present rarely upto 8 months post-infection. IgM antibody is also produced in secondary and tertiary dengue infections, although the response in some secondary and probably most tertiary infections is low level and transient. Patients with primary dengue infections usually are IgM positive & IgG negative with higher IgM concentrations , whereas patients with secondary infections are usually both IgG and IgM Dengue Shock Syndrome positive with higher IgG concentrations.
Positive results obtained with single serum samples are only provisional and do not necessarily indicate current dengue infection, but point to an infection in the previous 2 to 3 months. Similarly, a negative result with an acute-phase sample may be false-negative if the sample was taken before detectable IgM appeared. Hence accurate serologic diagnosis depends on demonstration of significant (fourfold or greater) rise in antibody titer between acute- and convalescent-phase serum samples.
All flaviviruses (Tick-borne encephalitis virus, Japanese encephalitis virus, Dengue virus) have common group epitopes on the envelope protein that result in extensive crossreactions in serologic tests. Hence patients suffering from other flavivirus infections may give a false positive dengue test.
Differential diagnoses during the acute phase of illness should include measles, rubella, influenza, typhoid, leptospirosis, malaria, other viral hemorrhagic fevers, and any other disease that may present as a nonspecific viral syndrome.

Test technique: Enzyme Immunoassay


Diabetes Mellitus is a common disorder of carbohydrate metabolism characterised by glucose underutilisation & hyperglycemia. Diabetes can be caused by auto - immune destruction of the B-cells of the pancreas or resistance of the peripheral tissues to insulin.

Blood glucose estimation (Fasting and Post prandial) are necessary to diagnose diabetes. To differentiate/identify Type I or Insulin Dependent Diabetes Mellitus (IDDM) versus Type II or Non Insulin Dependent Diabetes Mellitus (NIDDM), insulin assay is to be carried out.

Monitoring of treatment to prevent complications associated with Diabetes Mellitus is achieved by estimation of Glycosylated hemoglobin (HbA1c). This assay enables a view of controlled or uncontrolled status of diabetes over a period of 2-4 months. Thus a blood glucose estimation gives information about a 24 hour status where as HbA1c evaluates a blood glucose over a 2-4 month period. Increase in HbA1c value indicates risk for developing complications associated with diabetes.

Organs commonly affected due to complications associated with Diabetes Mellitus are kidney, heart, eyes & joints. Creatinine is a sensitive parameter for detecting altered renal functions. Microalbuminuria serves as a useful parameter to identify patients at risk for development of diabetic nephropathy. Diabetes with increased LDL cholesterol & triglycerides is associated with high risk of coronary heart disease. Uric acid estimation is necessary to rule out gout which is seen in 10-15% of diabetic patients.

Thus investigations are necessary not only to diagnose diabetes but to monitor it so as to avoid associated complications.


GLUCOSE, FASTING, PLASMA/SERUM

Glucose evaluations are used in the diagnosis & monitoring of carbohydrate metabolism disorders including Diabetes mellitus, Diabetic Acidosis and Keto- Acidosis, dehydration, coma, Hypoglycemia- (neonatal & idiopathic), Neuroglycopenia, and Islet Cell Carcinoma.

Test Technique: Hexokinase


GLUCOSE, FASTING, PLASMA/SERUM

Glucose evaluations are used in the diagnosis & monitoring of carbohydrate metabolism disorders including Diabetes mellitus, Diabetic Acidosis and Keto- Acidosis, dehydration, coma, Hypoglycemia- (neonatal & idiopathic), Neuroglycopenia, and Islet Cell Carcinoma.

Test Technique: Hexokinase

GLUCOSE, POST-PRANDIAL, PLASMA/SERUM


Post- prandial Glucose level is evaluated to establish the diagnosis of Diabetes mellitus. It is advisable to evaluate post- prandial Glucose levels along with Fasting Glucose.

It is used as part of the work up for Hypertriglyceridemia, Neuropathy, Retinopathy, Glucosuria and for certain type of renal diseases, Impotence, Vulvovaginitis, blurred vision, fatigue and some instances of Urinary Tract Infections.

Causes of Post-prandial hypoglycemia include alimentary type (commonly secondary to prior gastrointestinal surgery), reactive hypoglycemia without prior gastrointestinal surgery - alimentary or spontaneous. Hypoglycemia may be functional, idiopathic, indeterminate. Some prediabetic individuals may have hypoglycemia in initial stages. leucine-induced or fructose-induced hypoglycemia could occur. Galactosemia may be associated with hypoglycemia.

Test method: Spectrophotometry

GLYCOSYLATED HEMOGLOBIN, BLOOD

Current methods of assessing control in-patients with diabetes mellitus include measurement of blood and plasma glucose. These glucose measurements reflect acute changes and not the long-term aspects of diabetic control. A more useful technique for assessing the control of diabetes is the measurement of glycosylated hemoglobins; that is hemoglobins with glucose or glucose phosphate moieties bound to the amino terminal valine of one or both beta chains.

The level of Hemoglobin A1c, which compose 3% to 6% of the total hemoglobin in healthy individuals is proportional to both the average glucose concentration and the life span of the red blood cells in the circulation. The measurement of HbA1c has therefore been accepted for the clinical management of diabetes through routine monitoring. Glycosylated hemoglobins is an index of mean plasma glucose for preceding average 120 days. Increased levels of HbA1c correlate with lack of glucose control. In diabetics with good glucose control the amount of HbA1c may return to the reference interval.

Limitations:
Assay Interferences occur by Hb variants derivatives -Hb S trait, Hb C trait, carbamylated Hb, acetylated Hb in-patients taking aspirin.

Specimens from patients with hemolytic anemia will exhibit decrease glycated hemoglobin values due to shorter life span of the red cells. Glycosylated hemoglobins results from patients with HbSS, HbCC, and HbSC and HbD must be interpreted with caution, given the pathological processes, including anemia, increased red cell turnover, transfusion requirements, that adversely impact HbA1c as a marker of long-term glycemic control. In these conditions, alternative forms of testing such as glycated serum protein (fructosamine) should be considered.

Specimens from patients with polycythemia or post-splenectomy may exhibit increase glycated hemoglobin values due to a somewhat longer life span of the red cells.

Test method: High-Pressure Liquid Chromatography (HPLC)


GLUCOSE, FASTING, PLASMA/SERUM

Glucose evaluations are used in the diagnosis & monitoring of carbohydrate metabolism disorders including Diabetes mellitus, Diabetic Acidosis and Keto- Acidosis, dehydration, coma, Hypoglycemia- (neonatal & idiopathic), Neuroglycopenia, and Islet Cell Carcinoma.

Test Technique: Hexokinase

GLUCOSE, POST-PRANDIAL, PLASMA/SERUM

Post- prandial Glucose level is evaluated to establish the diagnosis of Diabetes mellitus. It is advisable to evaluate post- prandial Glucose levels along with Fasting Glucose.

It is used as part of the work up for Hypertriglyceridemia, Neuropathy, Retinopathy, Glucosuria and for certain type of renal diseases, Impotence, Vulvovaginitis, blurred vision, fatigue and some instances of Urinary Tract Infections.

Causes of Post-prandial hypoglycemia include alimentary type (commonly secondary to prior gastrointestinal surgery), reactive hypoglycemia without prior gastrointestinal surgery - alimentary or spontaneous. Hypoglycemia may be functional, idiopathic, indeterminate. Some prediabetic individuals may have hypoglycemia in initial stages. leucine-induced or fructose-induced hypoglycemia could occur. Galactosemia may be associated with hypoglycemia.

Test method: Spectrophotometry

GLYCOSYLATED HEMOGLOBIN, BLOOD

Current methods of assessing control in-patients with diabetes mellitus include measurement of blood and plasma glucose. These glucose measurements reflect acute changes and not the long-term aspects of diabetic control. A more useful technique for assessing the control of diabetes is the measurement of glycosylated hemoglobins; that is hemoglobins with glucose or glucose phosphate moieties bound to the amino terminal valine of one or both beta chains.

The level of Hemoglobin A1c, which compose 3% to 6% of the total hemoglobin in healthy individuals is proportional to both the average glucose concentration and the life span of the red blood cells in the circulation. The measurement of HbA1c has therefore been accepted for the clinical management of diabetes through routine monitoring. Glycosylated hemoglobins is an index of mean plasma glucose for preceding average 120 days. Increased levels of HbA1c correlate with lack of glucose control. In diabetics with good glucose control the amount of HbA1c may return to the reference interval.

Limitations:
Assay Interferences occur by Hb variants derivatives -Hb S trait, Hb C trait, carbamylated Hb, acetylated Hb in-patients taking aspirin.

Specimens from patients with hemolytic anemia will exhibit decrease glycated hemoglobin values due to shorter life span of the red cells. Glycosylated hemoglobins results from patients with HbSS, HbCC, and HbSC and HbD must be interpreted with caution, given the pathological processes, including anemia, increased red cell turnover, transfusion requirements, that adversely impact HbA1c as a marker of long-term glycemic control. In these conditions, alternative forms of testing such as glycated serum protein (fructosamine) should be considered.

Specimens from patients with polycythemia or post-splenectomy may exhibit increase glycated hemoglobin values due to a somewhat longer life span of the red cells.

Test method: Low Pressure Liquid Chromatography (LPLC)


GLUCOSE, FASTING, PLASMA/SERUM

Glucose evaluations are used in the diagnosis & monitoring of carbohydrate metabolism disorders including Diabetes mellitus, Diabetic Acidosis and Keto- Acidosis, dehydration, coma, Hypoglycemia- (neonatal & idiopathic), Neuroglycopenia, and Islet Cell Carcinoma.

Test Technique: Hexokinase

GLUCOSE, POST-PRANDIAL, PLASMA/SERUM

Post- prandial Glucose level is evaluated to establish the diagnosis of Diabetes mellitus. It is advisable to evaluate post- prandial Glucose levels along with Fasting Glucose.

It is used as part of the work up for Hypertriglyceridemia, Neuropathy, Retinopathy, Glucosuria and for certain type of renal diseases, Impotence, Vulvovaginitis, blurred vision, fatigue and some instances of Urinary Tract Infections.

Causes of Post-prandial hypoglycemia include alimentary type (commonly secondary to prior gastrointestinal surgery), reactive hypoglycemia without prior gastrointestinal surgery - alimentary or spontaneous. Hypoglycemia may be functional, idiopathic, indeterminate. Some prediabetic individuals may have hypoglycemia in initial stages. leucine-induced or fructose-induced hypoglycemia could occur. Galactosemia may be associated with hypoglycemia.

Test method: Spectrophotometry


GLYCOSYLATED HEMOGLOBIN, BLOOD

Current methods of assessing control in-patients with diabetes mellitus include measurement of blood and plasma glucose. These glucose measurements reflect acute changes and not the long-term aspects of diabetic control. A more useful technique for assessing the control of diabetes is the measurement of glycosylated hemoglobins; that is hemoglobins with glucose or glucose phosphate moieties bound to the amino terminal valine of one or both beta chains.

The level of Hemoglobin A1c, which compose 3% to 6% of the total hemoglobin in healthy individuals is proportional to both the average glucose concentration and the life span of the red blood cells in the circulation. The measurement of HbA1c has therefore been accepted for the clinical management of diabetes through routine monitoring. Glycosylated hemoglobins is an index of mean plasma glucose for preceding average 120 days. Increased levels of HbA1c correlate with lack of glucose control. In diabetics with good glucose control the amount of HbA1c may return to the reference interval.

Limitations:
Assay Interferences occur by Hb variants derivatives -Hb S trait, Hb C trait, carbamylated Hb, acetylated Hb in-patients taking aspirin.

Specimens from patients with hemolytic anemia will exhibit decrease glycated hemoglobin values due to shorter life span of the red cells. Glycosylated hemoglobins results from patients with HbSS, HbCC, and HbSC and HbD must be interpreted with caution, given the pathological processes, including anemia, increased red cell turnover, transfusion requirements, that adversely impact HbA1c as a marker of long-term glycemic control. In these conditions, alternative forms of testing such as glycated serum protein (fructosamine) should be considered.

Specimens from patients with polycythemia or post-splenectomy may exhibit increase glycated hemoglobin values due to a somewhat longer life span of the red cells.

Test method: Affinity Column Chromatography Method

DIRECT LDL CHOLESTEROL, SERUM
According to the recommendations of the NCEP, the treatment of high blood cholesterol is mainly based on the concentration of serum LDL cholesterol. Increased blood cholesterol level, especially LDL cholesterol, increases the risk for coronary heart disease (CHD). LDL oxidation promotes foam-cell formation, which is the origin of atherosclerosis, and also impairs endothelial cell function. Reduction of LDL cholesterol is associated with less progression and more regression of atherosclerosis on follow-up studies.

Clinical Utility:
The calculated LDL-C is not accurate when the triglycerides are > 400 mg/dl and can be 10-25% lower after a fat loaded meal compared to fasting results. Direct LDL-C measurements has better accuracy and precision.

Interpretation:
Levels below 100 mg/dl indicate Optimal, levels between 100-129 mg/dl indicate Near or above optimal, levels between 130-159 mg/dl indicate Borderline High, levels between 160-189 mg/dl indicate High Risk whereas levels above 190 mg/dl indicate Very High Risk.

Test Technique: Enzymatic Clearance

References:
Bachorik PS, et al. National Cholesterol Education Program recommendations for measurement of low-density lipoprotein cholesterol: executive summary. Clin Chem 1995; 41(10):1414-1420.
European atherosclerosis society international task force for prevention of coronary heart disease. Prevention of coronary heart disease: scientific background and new clinical guidelines. Nutr Metab Cardiovasc Dis 1992; 2:113-156.
Expert Panel, The. Summary of the second report of the national cholesterol education panel (NCEP) expert panel on detection, evaluation, and treatment of high blood cholesterol in adults (Adult Treatment Panel II). JAMA 1993; 269(23):1421-1426 and 3015-23.


ELECTROLYTES (NA/K/CL), 24HRS URINE


Test method: ISE (Ion selective electrodes)


ELECTROLYTES (NA/K/CL), SERUM

Test Technique: ISE – Direct



ERYTHROCYTE SEDIMENTATION RATE, BLOOD

Erythrocyte sedimentation rate (ESR) is a non - specific phenomena and is clinically useful in the diagnosis and monitoring of disorders associated with an increased production of acute phase reactants. The ESR is increased in pregnancy from about the 3rd month and returns to normal by the 4th week post partum. ESR is influenced by age, sex, menstrual cycle and drugs (eg. corticosteroids, contraceptives). It is especially low (0 -1mm) in polycythaemia, hypofibrinogenemia or congestive cardiac failure and when there are abnormalities of the red cells such as poikilocytosis, spherocytosis or sickle cells.

Test Technique: Rate of fall of red cells (sedimentation) (Modified Westergren's method)


ERYTHROPOIETIN, SERUM

Erythropoietin (EPO) is secreted by the kidney and binds to a specific receptor on erythroid progenitor cells and facilitates their differentiation. The clearance rate of EPO is not affected by its serum concentrations or tissue utilization, hence, circulating EPO concentrations reflect the EPO synthesis rate. EPO concentration is elevated in polycythemia secondary to tissue hypoxia (e.g., Cyanotic heart disease and high altitudes), Familial erythrocytosis, disorders with increased erthrocyte hemoglobin oxygen affinity, in the presence of EPO-producing tumors, and sometimes in post-kidney transplantation. Normal or subnormal EPO concentrations are observed in polycythemia rubra vera. Renal failure can cause a decrease in EPO production leading to low erythrocyte mass. EPO deficiency is observed in a variety of chronic disorders including infection. EPO levels in HIV-infected patients can increase markedly in response to zidovudine treatment.

Test method: Chemiluminescensce


ESCHERICHIA COLI K1 CSF
The current test enables rapid qualitative detection of bacterial antigen of Escherichia coli K1 in CSF, urine, body fluids and serum. The test can also be used for confirmation of organism identity from plate cultures.

Escherichia coli is a common cause of meningitis and sepsis in the newborn infant, and the large majority of isolates from these infections produce a polysialic acid (PSA) capsular polysaccharide, the K1 antigen, that protects the bacterial cell from immune attack. It is also one of the most frequent causes of urinary tract infections and septicemia in adults

The current test is of utmost importance in diagnosis of E coli K1 meningitis. Bacterial antigen testing in CSF may provide true-positive results in patients with negative culture & gram stain results and cell counts & chemistries consistent with bacterial meningitis. In addition, the rapid results enable the physician to implement early and specific antimicrobial therapy rather than the broad-coverage therapy that is usually instituted until culture and antimicrobial susceptibility results are available. CSF is the specimen of choice in patients who have not been treated or who have received therapy for <24 hours, whereas urine testing is advised in patients who have undergone treatment for >24 hours. In successfully treated bacterial meningitis patients, bacterial antigen may remain detectable in body fluids for many days, with higher concentrations in urine and serum than in CSF.

False positive antigen detection results can be seen due to nonspecific cross-reactions, presence of Rheumatoid factor, blood, hemolyzed erythrocytes, and high concentrations of protein in the specimen. In addition, antigenic cross-reactions with the normal urethral flora can cause false-positive results in urine. Specimens collected very early in disease, may yield false negative results due to low concentrations of antigen in clinical specimens. Hence, it is advised to retest another specimen if symptoms persist or intensify. The test is a supportive test and is not to be used for definitive diagnosis. All results must be correlated with clinical history and other laboratory findings.

Test Method: Latex Particle Agglutination


ESTRADIOL, SERUM

Estradiol plays an essential role throughout the human menstrual cycle. During the early follicular phase, the estradiol level is relatively constant and low. By day seven, the dominant follicle is established and the estradiol level rises significantly. The elevated estradiol level suppresses the FSH level by negative feedback on the hypothalamus and pituitary gland and triggers a rapid rise of LH. The estradiol level falls significantly as LH reaches its peak. Normally, ovulation occurs 10 to 12 hours after the LH peak and 24 to 36 hours after the estradiol peak. During the luteal phase the estradiol level increases, achieving a maximum level about 8 days after ovulation. The elevated estradiol level is involved in the regression of the corpus luteum. Unless fertilization of the ovum takes places, the estradiol level decreases, signaling the start of a new cycle.

In normal, non-pregnant females, estradiol is secreted mainly by the combined function of the theca and granulosa cells of the developing follicle and the corpus luteum. During pregnancy, the placenta is a source of estradiol secretion. Estradiol enters the blood stream where 1 to 3% is non-protein bound, 40% is bound to sex-hormone binding globulin (SHBG) and the remainder is bound to albumin. The primary function of estradiol is to stimulate growth of the female sex organs and development of secondary sexual characteristics.

Elevated estradiol levels in females may also result from primary or secondary ovarian hyper function. Very high estradiol levels are found during the induction of ovulation for assisted reproduction therapy or in pregnancy. Measuring the circulating levels of estradiol is important for assessing ovarian function and monitoring follicular development for assisted reproduction protocols.

Decreased estradiol levels in females may result from either the lack of ovarian synthesis (primary ovarian hypo function and menopause) or a lesion in the hypothalamus-pituitary axis (Secondary ovarian hypo function).

Estradiol levels are normally low in males. Elevated estradiol levels in males may be due to increased aromatization of androgens, resulting in gynecomastia.

Heterophilic antibodies in human serum can react with reagent immunoglobulins, interfering with in vitro immunoassays. Patients routinely exposed to animals or to animal serum products can be prone to this interference and anomalous values may be observed.

Hormone assay values are to be correlated with the age and clinical status of the patient irrespective of whether the values are appearing in the 'In Range' or 'Out of Range' columns.

Test method: Chemiluminescence.


ESTRADIOL, SERUM

Estradiol plays an essential role throughout the human menstrual cycle. During the early follicular phase, the estradiol level is relatively constant and low. By day seven, the dominant follicle is established and the estradiol level rises significantly. The elevated estradiol level suppresses the FSH level by negative feedback on the hypothalamus and pituitary gland and triggers a rapid rise of LH. The estradiol level falls significantly as LH reaches its peak. Normally, ovulation occurs 10 to 12 hours after the LH peak and 24 to 36 hours after the estradiol peak. During the luteal phase the estradiol level increases, achieving a maximum level about 8 days after ovulation. The elevated estradiol level is involved in the regression of the corpus luteum. Unless fertilization of the ovum takes places, the estradiol level decreases, signaling the start of a new cycle.

In normal, non-pregnant females, estradiol is secreted mainly by the combined function of the theca and granulosa cells of the developing follicle and the corpus luteum. During pregnancy, the placenta is a source of estradiol secretion. Estradiol enters the blood stream where 1 to 3% is non-protein bound, 40% is bound to sex-hormone binding globulin (SHBG) and the remainder is bound to albumin. The primary function of estradiol is to stimulate growth of the female sex organs and development of secondary sexual characteristics.

Elevated estradiol levels in females may also result from primary or secondary ovarian hyper function. Very high estradiol levels are found during the induction of ovulation for assisted reproduction therapy or in pregnancy. Measuring the circulating levels of estradiol is important for assessing ovarian function and monitoring follicular development for assisted reproduction protocols.

Decreased estradiol levels in females may result from either the lack of ovarian synthesis (primary ovarian hypo function and menopause) or a lesion in the hypothalamus-pituitary axis (Secondary ovarian hypo function).

Estradiol levels are normally low in males. Elevated estradiol levels in males may be due to increased aromatization of androgens, resulting in gynecomastia.

Heterophilic antibodies in human serum can react with reagent immunoglobulins, interfering with in vitro immunoassays. Patients routinely exposed to animals or to animal serum products can be prone to this interference and anomalous values may be observed.

Hormone assay values are to be correlated with the age and clinical status of the patient irrespective of whether the values are appearing in the 'In Range' or 'Out of Range' columns.

Test method: Chemiluminescence.


ESTRIOL, UNCONJUGATED, SERUM


During pregnancy, as the fetus develops, Estriol production increases resulting in a early three fold rise in circulating Estriol levels during the 1st & 2nd trimester. The free and total Estriol concentration reach approximately 15 & 250 ng / mL at term. After 40 weeks, Estriol levels gradually subside, declining by roughly 12 percent per week.

LOW LEVELS:
Persistently low or rapidly falling Estriol levels suggest fetal distress. Serial determinations have been used in the management of pregnancies complicated by Diabetes, Hypertension, prolonged gestation and uncertain LMP dates.

Test method: Chemiluminescence.

Reference range for males & non-Pregnant Females is taken from Teitz Text Book of Clinical Chemistry, 4th Edition.

The clone for “ER” antibody is “ER – SP1”.


FACTOR VIII ACTIVITY, PLASMA

Normal plasma activity : 60 - 150% of normal
Severe haemophilia : < 1%
Moderate Haemophilia : 1 - 5%
Mild haemophilia : 5 - 20%
Von Willebrand disease: 20 - 50%

Test method: Clotting based assay.


FERRITIN, SERUM

Stored iron represents about 25% of total body iron and most of this iron is stored as Ferritin. Ferritin is found in serum in low concentrations and is directly proportional to the body's iron stores. Serum Ferritin concentration, when considered with other factors such as serum iron, iron-binding capacity and tissue iron stores is valuable in the diagnosis of iron deficiency anemia, anemia of chronic infection and conditions such as thalassemia and hemochromatosis that are associated with iron overload. Measurement of serum Ferritin is particularly valuable in distinguishing iron deficiency anemia caused by low iron stores from those resulting from inadequate iron utilization.

Serum Ferritin values are elevated in the presence of the following conditions and do not reflect actual body iron stores: 1.Inflammation 2.Significant tissue destruction 3.Liver diseases 4.Malignancies such as acute leukemia and Hodgkin's disease 5.Therapy with iron supplements. Heterophilic antibodies in human serum can react with reagent immunoglobulins, interfering with in vitro immunoassays. Patients routinely exposed to animals or to animal serum products can be prone to this interference and anomalous values may be observed.

Test method: Chemiluminescence.


FERTILITY PANEL, MALE, SERUM

Luteinising Hormone (LH) and Follicle Stimulating Hormone (FSH) are useful to distinguish Primary Gonadal failure from Secondary Gonadal failure due to Hypothalamic / pituitary dysfunction. These are also useful in evaluating Testicular Dysfunction in men.
LH is used to assess Leydig cell function in males.
FSH, LH and Testosterone are low in Kallmann's is Syndrome.
Isolated LH deficiency is a variant of Kallmann's syndrome.
Elevated basal LH with high LH / FSH ratio in non-ovulating females could indicate Stein- Leventhal syndrome.
Prolactin levels may be elevated in Pituitary tumors, Amenorrhea & Polycystic Ovarian Syndrome.

Hormone assay values are to be correlated with the age and clinical status of the patient irrespective of whether the values are appearing in the 'In Range' or 'Out of Range' columns.

Test method: Chemiluminescence.


FOLIC ACID, SERUM

Folates are compounds of pteroylglutamic acid (PGA) that function as coenzymes in metabolic reactions involving the transfer of single-carbon units from a donor to a recipient compound. Folate, with vitamin B12, is essential for DNA synthesis, which is required for normal red blood cell maturation. Human obtain folate from dietary sources including fruits, green and leafy vegetables, yeast, and organ meats. Folate is absorbed through the small intestine and stored in the liver.

Low folate intake, malabsorption as result of gastrointestinal diseases, pregnancy, and drugs such as phenytoin are causes of folate deficiency. Folate deficiency is also associated with chronic alcoholism. Folate and vitamin B12 deficiency impair DNA synthesis, causing macrocytic anemias. These anemias are characterized by abnormal maturation of red blood cell precursors in the bone marrow, the presence of megaloblasts, and decreased red blood cell survival.

Since both folate and vitamin B12 deficiency can cause macrocytic anemia, appropriate treatment depends on the differential diagnosis of the deficiency. Serum folate measurement provides an early index of folate status. However, folate is much more concentrated in red blood cells than in serum so the red blood cell folate measurement more closely reflects tissue stores. Red blood cell folate concentration is considered the most reliable indicator of folate status.

Methotrexate and Leucovorin interfere with folate measurement because these drugs cross-react with folate binding proteins.

Test method: Chemiluminescence.


FREE TESTOSTERONE, SERUM

Most circulating Testosterone is bound to a specific carrier protein usually called Sex Hormone - Binding Globulin (SHBG) or Testosterone Binding Globulin (TeBG). A small portion of testosterone exists in the free & unbound state available for entry into the cells of target organs. Free Testosterone is probably the physiologically active component of testosterone.

The serum Free Testosterone assay was developed because the measurement of total Testosterone does not always give an accurate picture of the amount of testosterone available to target organ cells. Free Testosterone estimation is useful for suspected increases in physiologically active testosterone. An apparent inverse correlation of free Testosterone with age is noted in adult males.

The below mentioned are the guidelines for age related
Referance Ranges of Free Testosterone.

FREE TESTOSTERONE:
MALE (1-10 YRS): 0.15 - 0.6 pg/mL
MALE (20-39 YRS): 8.8 - 27.0 pg/mL
MALE (40-59 YRS): 7.2 - 23.0 pg/mL
MALE (60-80 YRS): 5.6 - 19.0 pg/mL
FEMALES:
FEMALE (1-10 YRS): 0.15 - 0.6 pg/mL
FEMALES (20-39 YRS): 0.15 - 2.57 pg/mL
FEMALES (40-59 YRS): 0.15 - 2.03 pg/mL
FEMALES (60-80 YRS): 0.15 - 1.55 pg/mL

Test method: Radio Immunoassay.


FREE THYROXINE (FT4), SERUM

Thyroxine (3, 5, 3', 5' - tetraiodothyronine, L-thyroxine or T4) is a hormone synthesized and secreted by the thyroid gland and plays an important role in regulating metabolism. Secretion into the circulation is in response to the pituitary hormone TSH (Thyroid Stimulating Hormone) and is regulated by a negative feedback mechanism involving the thyroid gland, pituitary gland and hypothalamus.

In the circulation, 99.95% of T4 is reversibly bound to transport proteins, primarily thyroxine-binding globulin (TBG) and to a lesser extent albumin and thyroxine-binding prealbumin (TBPA). The remaining T4 is not bound to transport proteins, but is free in the circulation. This unbound fraction, or free T4 (FT4), is both metabolically active and a precursor to triiodothyronine (T3).

Free T4 levels correlate with T4 secretion and metabolism. In hypothyroidism and hyperthyroidism, FT4 levels parallel changes in Total T4 levels. Measuring Free T4 is useful when altered levels of Total T4 occur due to change in T4 binding proteins, especially TBG. TBG levels remain relatively constant in healthy individual, but certain conditions, such as pregnancy and steroid therapy can alter these levels. In these conditions, free T4 levels are unchanged, while Total T4 levels parallel the changes in TBG.

Below mentioned are the guidlines for age related reference ranges for FT4 in ng/dl
---------------------------------------------------------------------------------------------------------
Adults 0.93 – 1.71
Pregnancy
First Trimester 0.94 – 1.52
Second Trimester 0.75 – 1.32
Third Trimester 0.65 – 1.21

Children and Adolescents
0 – 3 days 0.66 – 2.71
4 – 30 days 0.83 – 3.09
2 - 12 months 0.48 – 2.34
2 – 6 years 0.85 – 1.75
7 – 12 years 0.90 – 1.67
12 – 19 years 0.93 – 1.60
---------------------------------------------------------------------------------------------------------
Test method: Chemiluminescence.

FREE THYROXINE (FT4), SERUM

Thyroxine (3, 5, 3', 5' - tetraiodothyronine, L-thyroxine or T4) is a hormone synthesized and secreted by the thyroid gland and plays an important role in regulating metabolism. Secretion into the circulation is in response to the pituitary hormone TSH (Thyroid Stimulating Hormone) and is regulated by a negative feedback mechanism involving the thyroid gland, pituitary gland and hypothalamus.

In the circulation, 99.95% of T4 is reversibly bound to transport proteins, primarily thyroxine-binding globulin (TBG) and to a lesser extent albumin and thyroxine-binding prealbumin (TBPA). The remaining T4 is not bound to transport proteins, but is free in the circulation. This unbound fraction, or free T4 (FT4), is both metabolically active and a precursor to triiodothyronine (T3).

Free T4 levels correlate with T4 secretion and metabolism. In hypothyroidism and hyperthyroidism, FT4 levels parallel changes in Total T4 levels. Measuring Free T4 is useful when altered levels of Total T4 occur due to change in T4 binding proteins, especially TBG. TBG levels remain relatively constant in healthy individual, but certain conditions, such as pregnancy and steroid therapy can alter these levels. In these conditions, free T4 levels are unchanged, while Total T4 levels parallel the changes in TBG.

Below mentioned are the guidlines for age related reference ranges for FT4.
---------------------------------------------------------------------------------------------------------
New Born (1-4 days) 2.2 - 5.3 ng/dL
Children 0.8 - 2.7 ng/dL

Pregnancy
1st Trimester 0.7 - 2.0 ng/dL
2nd & 3rd Trimester 0.5 - 1.6 ng/dL
---------------------------------------------------------------------------------------------------------
Test method: Chemiluminescence.

Reference:
1. Burtis
C.A., Ashwood E. R. Bruns D.E. Teitz textbook of Clinical Chemistry and Molecular Diagnostics, 4th Edition.


FREE THYROXINE (FT4), SERUM

Thyroxine (3, 5, 3', 5' - tetraiodothyronine, L-thyroxine or T4) is a hormone synthesized and secreted by the thyroid gland and plays an important role in regulating metabolism. Secretion into the circulation is in response to the pituitary hormone TSH (Thyroid Stimulating Hormone) and is regulated by a negative feedback mechanism involving the thyroid gland, pituitary gland and hypothalamus.

In the circulation, 99.95% of T4 is reversibly bound to transport proteins, primarily thyroxine-binding globulin (TBG) and to a lesser extent albumin and thyroxine-binding prealbumin (TBPA). The remaining T4 is not bound to transport proteins, but is free in the circulation. This unbound fraction, or free T4 (FT4), is both metabolically active and a precursor to triiodothyronine (T3).

Free T4 levels correlate with T4 secretion and metabolism. In hypothyroidism and hyperthyroidism, FT4 levels parallel changes in Total T4 levels. Measuring Free T4 is useful when altered levels of Total T4 occur due to change in T4 binding proteins, especially TBG. TBG levels remain relatively constant in healthy individual, but certain conditions, such as pregnancy and steroid therapy can alter these levels. In these conditions, free T4 levels are unchanged, while Total T4 levels parallel the changes in TBG.

Below mentioned are the guidlines for age related reference ranges for FT4.
---------------------------------------------------------------------------------------------------------
New Born (1-4 days) 2.2 - 5.3 ng/dL
Children 0.8 - 2.7 ng/dL

Pregnancy
1st Trimester 0.7 - 2.0 ng/dL
2nd & 3rd Trimester 0.5 - 1.6 ng/dL
---------------------------------------------------------------------------------------------------------
Test method: Chemiluminescence.

Reference:
1. Burtis
C.A., Ashwood E. R. Bruns D.E. Teitz textbook of Clinical Chemistry and Molecular Diagnostics, 4th Edition.


FREE TRIIODOTHYRONINE (FT3), SERUM

Triiodothyronine (3,5,3'-L-Triiodothyronine, T3) is a hormone synthesized and secreted from the thyroid gland and is also formed by peripheral deiodination of thyroxine (T4). T3 and T4 are secreted into the circulation in response to thyroid stimulating hormone (TSH) and play an important role in regulating metabolism. The T3 and T4 secretion are regulated by a negative feedback mechanism involving the thyroid gland, pituitary gland and hypothalamus.

In the circulation, 99.7% of T3 is reversibly bound to transport proteins, primarily thyroxine-binding globulin (TBG) and to a lesser extent albumin and prealbumin. The remaining T3 does not bind to transport proteins, but is free in the circulation. This unbound fraction of the Total T3 concentration is free triiodothyronine (Free T3, FT3). Unbound T3 is metabolically active.

Free T3 levels correlate with T3 secretion and metabolism. In hypothyroidism and hyperthyroidism, Free T3 levels parallel changes in Total T3 levels. However, measuring Free T3 is useful when altered levels of Total T3 occur due to changes in T3 binding proteins, especially TBG. TBG levels remain relatively constant in healthy individuals, but certain conditions such as pregnancy and steroid therapy, can alter these levels. In these conditions, Free T3 levels are unchanged, while Total T3 levels parallel the changes in TBG.

Below mentioned are the guidlines for age related reference ranges for FT3.
---------------------------------------------------------------------------------------------------------
Cord Blood 1.5 - 3.9 pg/mL
Children 2.1 - 4.4 pg/mL
Pregnancy 2.0 - 3.8 pg/mL
---------------------------------------------------------------------------------------------------------

Test method: Chemiluminescence.

Reference:
1. Burtis
C.A., Ashwood E. R. Bruns D.E. Teitz textbook of Clinical Chemistry and Molecular Diagnostics, 4th Edition.


FREE TRIIODOTHYRONINE (FT3), SERUM

Triiodothyronine (3,5,3'-L-Triiodothyronine, T3) is a hormone synthesized and secreted from the thyroid gland and is also formed by peripheral deiodination of thyroxine (T4). T3 and T4 are secreted into the circulation in response to thyroid stimulating hormone (TSH) and play an important role in regulating metabolism. The T3 and T4 secretion are regulated by a negative feedback mechanism involving the thyroid gland, pituitary gland and hypothalamus.

In the circulation, 99.7% of T3 is reversibly bound to transport proteins, primarily thyroxine-binding globulin (TBG) and to a lesser extent albumin and prealbumin. The remaining T3 does not bind to transport proteins, but is free in the circulation. This unbound fraction of the Total T3 concentration is free triiodothyronine (Free T3, FT3). Unbound T3 is metabolically active.

Free T3 levels correlate with T3 secretion and metabolism. In hypothyroidism and hyperthyroidism, Free T3 levels parallel changes in Total T3 levels. However, measuring Free T3 is useful when altered levels of Total T3 occur due to changes in T3 binding proteins, especially TBG. TBG levels remain relatively constant in healthy individuals, but certain conditions such as pregnancy and steroid therapy, can alter these levels. In these conditions, Free T3 levels are unchanged, while Total T3 levels parallel the changes in TBG.

Below mentioned are the guidlines for age related reference ranges for FT3.
---------------------------------------------------------------------------------------------------------
Cord Blood 1.5 - 3.9 pg/mL
Children 2.1 - 4.4 pg/mL
Pregnancy 2.0 - 3.8 pg/mL
---------------------------------------------------------------------------------------------------------

Test method: Chemiluminescence.

Reference:
1. Burtis
C.A., Ashwood E. R. Bruns D.E. Teitz textbook of Clinical Chemistry and Molecular Diagnostics, 4th Edition.


FSH & LH EVALUATION, SERUM


Circulating FSH levels vary throughout the menstrual cycle in response to Estradiol and Progesterone. A small but significant increase in circulating FSH accompanies the mid- cycle LH surge. FSH declines in the luteal phase in response to Estradiol and Progesterone production by the developing Corpus Luteum. FSH is elevated and gonadal steroids are depressed include Menopause, Premature Ovarian Failure, and Ovariactomy, while with Polycystic Ovarian Syndrome the LH / FSH ratio may be increased. At Menopause, FSH and LH increase sufficiently in response to diminished feed back mechanism of Gonadotropin release. Elevated concentration of LH may indicate Primary Amenorrhea, Menopause, Premature Ovarian Failure, Polycystic Ovarian Syndrome, or Hypergonadotropic Hypogonadism. The levels of LH & FSH in women are to be correlated with the day of the menstrual cycle.

FSH, LH and Testosterone regulate spermatogenesis by the Sertoli cells in seminiferous tubules of the testes. FSH may also be elevated in Klinefelter's Syndrome (Seminiferous Tubule Dysgenesis) or as a consequence of Sertoli cell Failure. Elevated concentration of LH and FSH accompanied by low concentration of gonadal steroids may result in infertility due to Gonadal Failure. Elevated concentration of LH may result in Primary Testicular Failure, Seminiferous Tubule Dysgenesis. (Klinefelter's Syndrome), Sertoli cell Failure & Hypergonadotropic Hypogonadism.

Hormone assay values are to be correlated with the age and clinical status of the patient irrespective of whether the values are appearing in the 'In Range' or 'Out of Range' columns.

Test method: Chemiluminescence.


FUNGAL SMEAR

Test method: Microscopy


FUNGAL STAIN

Direct microscopic examination of clinical specimens for fungal detection is useful as it provides a rapid and accurate diagnosis. This very important procedure can often provide the first microbiological proof of etiology in-patients with fungal infection.
---The potassium hydroxide preparation has been the recommended method for the direct microscopic examination of specimens. It is used to aid in detecting fungus element in thick mucoid material or in specimens containing keratinous material. The alkali digests cells and other tissue materials, enabling the fungus to be seen clearly.
---India ink or Nigrosin preparations are used for the direct microscopic examination of capsules of Cryptococus neoformans.
---All the fungi are gram positive in nature. The yeast cell is usually shows well-stained morphology but filamentous fungi in smear become desiccated and their morphological characteristics are lost.
---The filamentous bacteria like Nocardia species appears as acid fast purple or red colour.

Test Method : Microscopy.


G-6-PD ACTIVITY, BLOOD

G6PD deficiency in hemizygous (male) or homozygous (female) individuals may be readily detected by screening tests but it is more difficult to detect heterozygous female carriers. The clinical syndromes associated with this defect includes intravascular haemolysis, with or without methaemoglobinaemia and hemoglobinuria in association with a febrile infection and/or on exposure to oxidative drugs such as antimalarials (primaquine), sulfonamides, nitrofurans etc.

During or following a hemolytic crisis, G6PD deficiency may get masked due to reticulocytosis. Under these conditions detection of deficiency may require family studies. The screening test should only be performed after reticulocytes have returned to normal. If the dye decolorisation time is around or slightly above 60 minutes, G6PD quantitative assay is recommended. If the decolorisation time is more than 120 minutes, it suggests G6PD deficiency.

Test method: Dye decolorisation


G-6-PD, QUANTITATIVE, BLOOD

The gene for G6PD is on the X-chromosome, and therefore males, having only one G6PD gene, can be either normal or deficient hemizygotes. By contrast, females, who have two allelic genes, can be either normal homozygotes or heterozygotes with 'intermediate' enzyme activity or deficient homozygotes.
Red cells are likely to haemolyse on account of G6PD deficiency only if they have less than about 20% of normal enzyme activity.
G6PD activity decreases markedly as red cells age. Therefore, whenever a blood sample has a young red cell population, G6PD activity will be higher than normal, sometimes to the extent that a genetically deficient sample may yield a value within the normal range. This will be usually, but not always, associated with a high reticulocytosis.
In most cases, a normal value in a female means that she is a normal homozygote, and the value below 10% of low normal means that she is a deficient homozygote. Any value between 10 and 90% of normal usually means a heterozygote, except for the complicating effect of reticulocytosis.

Test method: Kinetic determination of G6PD


G-GLUTAMYL TRANSFERASE, SERUM

Gamma Glutamyl Transferase catalyses the transfer of glutamic acid from one peptide to another peptide or amino acid.

Test Technique: G-glutamyl-carboxy-nitroanilide

REFERENCE RANGES FOR GLUCOSE ONLY VALID IF PATIENT WAS FASTING


GLUCOSE RANDOM, PLASMA/SERUM

Random Glucose levels are useful in evaluation of carbohydrate metabolism disorders including Diabetes mellitus, Diabetic Acidosis and Ketoacidosis, Dehydration, work-up for Alcoholism, Coma, Neuroglycopenia and Islet Cell Carcinoma.

A fasting and a postprandial specimen are preferable to a random specimen for evaluation of possible diabetes mellitus.

Criteria for the diagnosis of diabetes mellitus
Symptoms of diabetes plus casual(random) plasma glucose concentration > 200 mg/dl (11.1 mmol/l). Casual(Random) is defined as any time of day without regard to time since last meal. The classic symptoms of diabetes include polyuria, polydipsia, and unexplained weight loss.
OR
2. FPG > 126 mg/dl (7.0 mmol/l). Fasting is defined as no caloric intake for at least 8 h.
OR
3. 2-h postload glucose > 200 mg/dl (11.1 mmol/l) during an OGTT. The test should be performed as described by WHO, using a glucose load containing the equivalent of 75 g anhydrous glucose dissolved in water.

Hypoglycemia (Blood glucose level <40mg%) occurs in starvation, overtreatment with insulin, hypothyroidism, hypoadrenalism and hypopituitarism.

Test technique: Hexokinase

Reference: Diagnosis and classification of diabetes mellitus, AMERICAN DIABETES ASSOCIATION, 2007


GLUCOSE TOLERANCE TEST (GTT-2)

Plasma Glucose load is 75gms.

Methodology: Photometry


GLUCOSE, FASTING, PLASMA

Glucose evaluations are used in the diagnosis & monitoring of carbohydrate metabolism disorders including Diabetes mellitus, Diabetic Acidosis and Keto- Acidosis, dehydration, coma, Hypoglycemia- (neonatal & idiopathic), Neuroglycopenia, and Islet Cell Carcinoma.


GLUCOSE, FASTING, PLASMA/SERUM

Glucose evaluations are used in the diagnosis & monitoring of carbohydrate metabolism disorders including Diabetes mellitus, Diabetic Acidosis and Keto- Acidosis, dehydration, coma, Hypoglycemia- (neonatal & idiopathic), Neuroglycopenia, and Islet Cell Carcinoma.

Test Technique: Hexokinase

GLUCOSE POST-PRANDIAL, PLASMA

Post- prandial Glucose level is evaluated to establish the diagnosis of Diabetes mellitus. It is advisable to evaluate post- prandial Glucose levels along with Fasting Glucose.

It is used as part of the work up for Hypertriglyceridemia, Neuropathy, Retinopathy, Glucosuria and for certain type of renal diseases, Impotence, Vulvovaginitis, blurred vision, fatigue and some instances of Urinary Tract Infections.

Causes of Post-prandial hypoglycemia include alimentary type (commonly secondary to prior gastrointestinal surgery), reactive hypoglycemia without prior gastrointestinal surgery - alimentary or spontaneous. Hypoglycemia may be functional, idiopathic, indeterminate. Some prediabetic individuals may have hypoglycemia in initial stages. leucine-induced or fructose-induced hypoglycemia could occur. Galactosemia may be associated with hypoglycemia.

GLYCOSYLATED HEMOGLOBIN, BLOOD

Current methods of assessing control in-patients with diabetes mellitus include measurement of blood and plasma glucose. These glucose measurements reflect acute changes and not the long-term aspects of diabetic control. A more useful technique for assessing the control of diabetes is the measurement of glycosylated hemoglobins; that is hemoglobins with glucose or glucose phosphate moieties bound to the amino terminal valine of one or both beta chains.

The level of Hemoglobin A1c, which compose 3% to 6% of the total hemoglobin in healthy individuals is proportional to both the average glucose concentration and the life span of the red blood cells in the circulation. The measurement of HbA1c has therefore been accepted for the clinical management of diabetes through routine monitoring. Glycosylated hemoglobins is an index of mean plasma glucose for preceding average 120 days. Increased levels of HbA1c correlate with lack of glucose control. In diabetics with good glucose control the amount of HbA1c may return to the reference interval.

Limitations:
Assay Interferences occur by Hb variants derivatives -Hb S trait, Hb C trait, carbamylated Hb, acetylated Hb in-patients taking aspirin.

Specimens from patients with hemolytic anemia will exhibit decrease glycated hemoglobin values due to shorter life span of the red cells. Glycosylated hemoglobins results from patients with HbSS, HbCC, and HbSC and HbD must be interpreted with caution, given the pathological processes, including anemia, increased red cell turnover, transfusion requirements, that adversely impact HbA1c as a marker of long-term glycemic control. In these conditions, alternative forms of testing such as glycated serum protein (fructosamine) should be considered.

Specimens from patients with polycythemia or post-splenectomy may exhibit increase glycated hemoglobin values due to a somewhat longer life span of the red cells.

Test method: Affinity Column Chromatography Method


GLYCOSYLATED HEMOGLOBIN, BLOOD


Current methods of assessing control in-patients with diabetes mellitus include measurement of blood and plasma glucose. These glucose measurements reflect acute changes and not the long-term aspects of diabetic control. A more useful technique for assessing the control of diabetes is the measurement of glycosylated hemoglobins; that is hemoglobins with glucose or glucose phosphate moieties bound to the amino terminal valine of one or both beta chains.

The level of Hemoglobin A1c, which compose 3% to 6% of the total hemoglobin in healthy individuals is proportional to both the average glucose concentration and the life span of the red blood cells in the circulation. The measurement of HbA1c has therefore been accepted for the clinical management of diabetes through routine monitoring. Glycosylated hemoglobins is an index of mean plasma glucose for preceding average 120 days. Increased levels of HbA1c correlate with lack of glucose control. In diabetics with good glucose control the amount of HbA1c may return to the reference interval.

Limitations:
Assay Interferences occur by Hb variants derivatives -Hb S trait, Hb C trait, carbamylated Hb, acetylated Hb in-patients taking aspirin.

Specimens from patients with hemolytic anemia will exhibit decrease glycated hemoglobin values due to shorter life span of the red cells. Glycosylated hemoglobins results from patients with HbSS, HbCC, and HbSC and HbD must be interpreted with caution, given the pathological processes, including anemia, increased red cell turnover, transfusion requirements, that adversely impact HbA1c as a marker of long-term glycemic control. In these conditions, alternative forms of testing such as glycated serum protein (fructosamine) should be considered.

Specimens from patients with polycythemia or post-splenectomy may exhibit increase glycated hemoglobin values due to a somewhat longer life span of the red cells.

Test method: High-Pressure Liquid Chromatography (HPLC)


GLYCOSYLATED HEMOGLOBIN, BLOOD

Current methods of assessing control in-patients with diabetes mellitus include measurement of blood and plasma glucose. These glucose measurements reflect acute changes and not the long-term aspects of diabetic control. A more useful technique for assessing the control of diabetes is the measurement of glycosylated hemoglobins; that is hemoglobins with glucose or glucose phosphate moieties bound to the amino terminal valine of one or both beta chains.

The level of Hemoglobin A1c, which compose 3% to 6% of the total hemoglobin in healthy individuals is proportional to both the average glucose concentration and the life span of the red blood cells in the circulation. The measurement of HbA1c has therefore been accepted for the clinical management of diabetes through routine monitoring. Glycosylated hemoglobins is an index of mean plasma glucose for preceding average 120 days. Increased levels of HbA1c correlate with lack of glucose control. In diabetics with good glucose control the amount of HbA1c may return to the reference interval.

Limitations:
Assay Interferences occur by Hb variants derivatives -Hb S trait, Hb C trait, carbamylated Hb, acetylated Hb in-patients taking aspirin.

Specimens from patients with hemolytic anemia will exhibit decrease glycated hemoglobin values due to shorter life span of the red cells. Glycosylated hemoglobins results from patients with HbSS, HbCC, and HbSC and HbD must be interpreted with caution, given the pathological processes, including anemia, increased red cell turnover, transfusion requirements, that adversely impact HbA1c as a marker of long-term glycemic control. In these conditions, alternative forms of testing such as glycated serum protein (fructosamine) should be considered.

Specimens from patients with polycythemia or post-splenectomy may exhibit increase glycated hemoglobin values due to a somewhat longer life span of the red cells.

Test method: Low Pressure Liquid Chromatography (LPLC)


GRAM STAIN


Gram stain is the most important staining method in bacteriology. It is the first and usually the only method employed for the diagnostic identification of bacteria in clinical specimens. It also serves to assess the quality of clinical specimens.

Interpretation of gram stained smears from clinical specimens involves consideration of staining characteristic, morphology of the etiological agent and presence of particular host cell types. It distinguishes two categories of genera: the Gram-positive, which stain dark purple, and the Gram-negative, which stain light red. A few species are 'Gram-variable', and tend to show a mixture of the two types of cells. Further details of the bacteria as any other special features, including unusual shapes (such as comma shaped Gram negative bacilli) are also observed.

Comparing Gram stain result to culture results is an excellent internal method for monitoring quality assurance.

Test method: Microscopy

GROWTH HORMONE STIMULATION TEST, SERUM

REFERENCE RANGE FOR GROWTH HORMONE STIMULATION TEST.
Post- stimulation normal peak levels of GH are 10 ng/mL or more. In children, GH levels 7.0 ng/mL or less and in adults GH levels of 5.0 ng/mL or less indicate GH deficiency. GH levels between normal and deficient states are considered as Indeterminate.

Growth Hormone (GH) is a polypeptide constituted by 191 amino acids and is secreted by anterior pituitary gland under control of hypothalamus through GH releasing hormone. GH secretion levels may be associated with secretion of other anterior pituitary hormones like Adreno- Cortico- Tropic Hormone (ACTH), Thyroid Stimulating Hormone (TSH) and Prolactin. Hypersecretion of GH results in gigantism or acromegaly and hyposecretion of GH results in dwarfism. Basal or random GH test with normal or low levels are not sensitive markers of GH deficiency.

Growth Hormone (GH) stimulation tests are performed due to their greater sensitivity as compared to GH levels, in clinically suspected individuals with GH deficiency. GH stimulation test is performed with administration of stimulants like insulin, levo- dopa or arginine and blood specimens are collected at 0, 30, 60, 90 and 120 minutes. Serum is used for evaluation of GH levels. Depending on the stimulant administered, GH levels reach their peak values in 60 minutes. Occasionally, with arginine administration, peak levels may be reached in 30 minutes.
More than one stimulation test is recommended to establish response to stimulation / provocation test. GH stimulation tests distinguish between primary and secondary pituitary- hypothalamic conditions resulting in GH deficiency but do not differentiate between pituitary vis- a- vis hypothalamic dysfunction as an etiology for GH deficiency.

GROWTH HORMONE STIMULATION TEST, SERUM

REFERENCE RANGE FOR GROWTH HORMONE STIMULATION TEST.
Post- stimulation normal peak levels of GH are 10 ng/mL or more. In children, GH levels 7.0 ng/mL or less and in adults GH levels of 5.0 ng/mL or less indicate GH deficiency. GH levels between normal and deficient states are considered as Indeterminate.

Growth Hormone (GH) is a polypeptide constituted by 191 amino acids and is secreted by anterior pituitary gland under control of hypothalamus through GH releasing hormone. GH secretion levels may be associated with secretion of other anterior pituitary hormones like Adreno- Cortico- Tropic Hormone (ACTH), Thyroid Stimulating Hormone (TSH) and Prolactin. Hypersecretion of GH results in gigantism or acromegaly and hyposecretion of GH results in dwarfism. Basal or random GH test with normal or low levels are not sensitive markers of GH deficiency.

Growth Hormone (GH) stimulation tests are performed due to their greater sensitivity as compared to GH levels, in clinically suspected individuals with GH deficiency. GH stimulation test is performed with administration of stimulants like insulin, levo- dopa or arginine and blood specimens are collected at 0, 30, 60, 90 and 120 minutes. Serum is used for evaluation of GH levels. Depending on the stimulant administered, GH levels reach their peak values in 60 minutes. Occasionally, with arginine administration, peak levels may be reached in 30 minutes.
More than one stimulation test is recommended to establish response to stimulation / provocation test. GH stimulation tests distinguish between primary and secondary pituitary- hypothalamic conditions resulting in GH deficiency but do not differentiate between pituitary vis- a- vis hypothalamic dysfunction as an etiology for GH deficiency.

The clone for “GH" antibody is “54/9 2A2”.


GROWTH HORMONE, SERUM

Human growth hormone (hGH, somatotropin) is a polypeptide originating in the anterior pituitary. It is 191 amino acids in length and has a molecular mass of approximately 22,000 daltons. Its metabolic effects are primarily anabolic. It promotes protein conservation and engages a wide range of mechanisms for protein synthesis. It also enhances glucose transport and facilitates the buildup of glycogen stores.

Measurement of hGH is primarily of interest in the diagnosis and treatment of various forms of inappropriate growth hormone secretion. Clinical disorders of hyposecretion include dwarfism and unattained growth potential. Hypersecretion is associated with gigantism and acromegaly.

Caution must be exercised in the clinical interpretation of growth hormone levels. These vary throughout the day, making it difficult to define a reference range or to judge an individual's status based on single determinations. Many factors are known to influence the rate of growth hormone secretion, including periods of sleep and wakefulness, exercise, stress, hypoglycemia, estrogens, corticosteroids, L-dopa, and others.

Growth hormone-deficient individuals have fasting/resting levels similar to those found in healthy individuals. Various challenge tests have therefore been devised to differentiate these groups. Thus with the onset of deep sleep or after 15 to 20 minutes of vigorous exercise, growth hormone levels normally show a rise. Other tests of growth hormone responsiveness are based on the administration of L-dopa, arginine and insulin. Propanolol and estrogen are sometimes given in conjuction with the primary stimulus to accentuate the response.

A small number of cases of dwarfism have been documented in which both the basal level and the response to challenge testing were normal. Such cases may involve tissue insensitivity to either growth hormone or somatomedins, or the presence of antibodies or immunoreactive but biologically inactive growth hormone.

REFERENCE RANGE FOR GROWTH HORMONE STIMULATION TEST.
Post- stimulation normal peak levels of GH are 10 ng/mL or more. In children, GH levels 7.0 ng/mL or less and in adults GH levels of 5.0 ng/mL or less indicate GH deficiency. GH levels between normal and deficient states are considered as Indeterminate.


HEPATITIS B SURFACE ANTIGEN, CONFIRMATION


This test uses the principle of specific antibody neutralisation to confirm the presence of HBsAg in human sera.

Positive result confirms the presence of Hepatitis B Surface Antigen in serum specimen.

Test Technique: Microparticle Enzyme Immuno-Assay / Electrochemiluminescence


HBsAg CONFIRMATION

Method: Microparticle Enzyme Immunoassay
Kit Used: HBsAg Confirmatory
Manufacturer: Abbott Axsym


HCV ABS IgG, SERUM

Hepatitis C Virus (HCV) is a blood borne flavivirus. It is one of the most important causes of post-blood transfusion as well as community acquired non-A non-B hepatitis and chronic liver failure. Although the majority of infected individuals may be asymptomatic, HCV infection may develop into chronic hepatitis, cirrhosis and/or increased risk of hepatocellular carcinoma.
HCV antibody is typically not detected until approximately 14 weeks after infection (or 5 weeks after appearance of the first biochemical marker of illness) and is almost always detectable by the late convalescent stage of infection. A negative result may also be observed due to loss of HCV antigen, years following resolution of infection. Infants born to hepatitis C infected mothers may have delayed seroconversion to anti-HCV. Hence a negative result should be evaluated cautiously with respect to clinical findings. It is to be noted that absence of HCV antibodies after 14 weeks of exposure is strong evidence against HCV infection.
Presence of HCV antibodies does not imply an active Hepatitis C infection but is indicative of both past and/or recent infection .It has been reported that as many as 90% of individuals receiving intravenous commercial immunoglobulin test falsely positive for HCV antibody. Also, patients with autoimmune liver disease may show a false positive HCV antibody result.
Limitations:-
This is just a rapid screening test and a positive result has to be confirmed by ELISA or PCR. A non reactive result does not exclude the possibility of exposure or infection with HCV. False reactive results may also occur due to non-specific binding of the sample to the membrane.

Test method: Enzyme Immunoassay (Rapid)


HEMOGLOBIN VARIANT ANALYSIS (HPLC), BLOOD

Determination of elevated levels of hemoglobin (Hb) A2 & F is the most practical means of diagnosing inheritance of the beta - thalassemia gene.

High performance liquid chromatography (HPLC) is a fast and accurate method for determining the presence and quantity of various Hb. The Hb Variant is a fully automated HPLC system which is used to separate & determine percentages of normal and abnormal Hb. The most commonly encountered abnormal Hb are Hb S, C, E & D in addition to beta - thalassemia and alpha - thalassemia.

Heterozygous & homozygous beta - thalassemia yield HbF ranges of 1 - 5 % & 80 - 100 % respectively. Normal range for HbA2 is between 1.75 % & 4 % while in heterozygous beta - thalassemia HbA2 levels between 4.0 % to 9.0 % are encountered.
Unknown peaks immediately prior to P2 peak are normal.
Test method: High Performance Liquid Chromatography (HPLC)


HEMOPHILIA PANEL

Factor VIII & IX deficiency may be either due to defective synthesis or excessive utilization with normal synthesis. Bioassays for coagulation factors are usually based on familiar screening and confirmatory tests - PT, PTT and mixing studies.


HEPATITIS A ABS,TOTAL
Evaluate Hepatitis A.


HEP A ABS ,IgM (EIA)
Differential diagnosis of Hepatitis; the presence of IgM antibodies to Hepatitis A virus is good evidence for acute Hepatitis A.

HEP B CORE ABS, IgM
IgM antibody to Hepatitis B core antigen is a reliable marker for acute disease for Hepatitis B viral infection. At times this marker is the only one demonstrated for the diagnosis of Hepatitis B viral infection.

HEP B SURF ABS ,TOT
Presence of Hepatitis B surface antibodies is an indicator of clinical recovery and subsequent immunity to Hepatitis B virus. This test is useful for evaluation of possible immunity in individuals who are at increased risk for exposure to the Hepatitis B, i.e., Hemodialysis Unit Personnel, Venipuncturists,etc. evaluation for the need for Hepatitis B immune globulin after needle stick injury. Evaluation of the need for Hepatitis B vaccine, and to follow immune status after Hepatitis B vaccine, and to follow immune status after Hepatitis B vaccine.

HEP B SURF AG - EIA
HBSAG appears in the blood about six weeks after infection and disappears by three months. Persistance of more than six months implies a carrier state. The enzyme immunoassay for the detection of Hepatitis B surface antigen is a highly sensitivity screening test and therefore yield false positive results. The proportion of false reactives will depend on the sensitivity and specificity of the test kit. Hence, it is recommended that a positive result of HBSAG must be confirmed using a different enzyme immunoassay kit or by using a confirmatory assay based on neutralisation with human anti Hepatitis B surface antibody based on clinical history, it may become necessary to test for presence of other markers of Hepatitis B virus infection.


HERPES SIMPLEX VIRUS 1&2 IgG & IgM, SERUM

Herpes simplex virus (HSV) is a widespread human pathogen with a tendency to induce lifelong latency in the sensory nerve ganglia, following the primary infection. Recurrent HSV infections are common due to endogenous reactivation of the virus .Precipitating factors for recurrence can include exposure to sunlight, fever, local trauma, trigeminal nerve manipulation, menstruation and emotional stress. HSV-1 and HSV-2 are 2 serologically distinguishable types. HSV 1 is primarily transmitted by contact with oral secretions and is usually associated with oral infections and lesions above the waist. HSV 2, on the other hand, is primarily transmitted by contact with genital secretions and is associated with genital infections and lesions below the waist. However the correlation between HSV type and the location of the lesion is not absolute. Transmission can occur from overtly infected persons as well as asymptomatic excretors. HSV is known to cause severe generalized and fatal infections in newborns and immunocompromised people.

Pregnant women who develop genital herpes are two to three times more likely to have spontaneous abortions or deliver a premature infant than are pregnant non-infected women. Active virus excretion in genital secretions of pregnant women may result in severe neonatal HSV infection that is associated with high morbidity and mortality rates if untreated.

HSV specific IgM becomes detectable after about one week of infection. Presence of IgM usually indicates recent or active recurrent infection. Specific IgG generally appears two to three weeks after primary infection, but may fall in titer after a few months. Sero-conversion of HSV -Specific IgG from negative to positive also suggests recent or active recurrent infection .However; some patients with recurring disease may not show an increase in titer. Detection of IgG allows assessment of the patient's immune status and provides serological evidence of prior exposure to HSV. Testing paired sera to demonstrate seroconversion is recommended for accurate diagnosis of recent (primary or recurrent) HSV infection.

Due to the strong serological cross-reactivity between HSV-1 and HSV-2, antibodies produced in response to infection by one virus can cross react with the other, though the response to the homologous, i.e., the infection virus is generally greater. For this reason, testing paired acute/convalescent specimens is useful to show change in antibody activity. Patients with indeterminate results should be tested with another sample taken 1-2 weeks after the first, if clinically indicated

Due to high seroprevalence of various community-related infectious diseases in the general Indian population, all results must be interpreted in the context of the total clinical history and supplementary findings of other investigative procedures.

Test method: Enzyme Immuno-Assay


HERPES SIMPLEX VIRUS DNA DETECTOR

Clinical Utility :
--This is a rapid test to detect HSV DNA and differentiate between HSV type I and II in clinical specimens.

Method:
DNA Polymerase Chain Reaction.

Interpretation:
Detection of a specific band indicates presence of HSV type1 DNA or HSV type 2 DNA in the given specimen.
No target specific amplification indicates absence of HSV DNA in the given sample.

All the results should always be correlated with clinical status and history of the patient

Limitations :
PCR is a highly sensitive technique; common reasons for paradoxical results are contamination during specimen collection, selection of inappropriate specimens and inherent PCR inhibitors in the specimen.


HERPES SIMPLEX VIRUS IgM, SERUM

HERPES SIMPLEX VIRUS-1 IgM, SERUM


Herpes simplex virus (HSV) is a widespread human pathogen with a tendency to induce lifelong latency in the sensory nerve ganglia, following the primary infection. Recurrent HSV infections are common due to endogenous reactivation of the virus .Precipitating factors for recurrence can include exposure to sunlight, fever, local trauma, trigeminal nerve manipulation, menstruation and emotional stress. HSV-1 and HSV-2 are 2 serologically distinguishable types. HSV 1 is primarily transmitted by contact with oral secretions and is usually associated with oral infections and lesions above the waist. HSV 2, on the other hand, is primarily transmitted by contact with genital secretions and is associated with genital infections and lesions below the waist. However the correlation between HSV type and the location of the lesion is not absolute. Transmission can occur from overtly infected persons as well as asymptomatic excretors. HSV is known to cause severe generalized and fatal infections in newborns and immunocompromised people.

Pregnant women who develop genital herpes are two to three times more likely to have spontaneous abortions or deliver a premature infant than are pregnant non-infected women. Active virus excretion in genital secretions of pregnant women may result in severe neonatal HSV infection that is associated with high morbidity and mortality rates if untreated.

HSV specific IgM becomes detectable after about one week of infection. Presence of IgM usually indicates recent or active recurrent infection. Specific IgG generally appears two to three weeks after primary infection, but may fall in titer after a few months. Sero-conversion of HSV -Specific IgG from negative to positive also suggests recent or active recurrent infection .However; some patients with recurring disease may not show an increase in titer. Detection of IgG allows assessment of the patient's immune status and provides serological evidence of prior exposure to HSV. Testing paired sera to demonstrate seroconversion is recommended for accurate diagnosis of recent (primary or recurrent) HSV infection.

Due to the strong serological cross-reactivity between HSV-1 and HSV-2, antibodies produced in response to infection by one virus can cross react with the other, though the response to the homologous, i.e., the infection virus is generally greater. For this reason, testing paired acute/convalescent specimens is useful to show change in antibody activity. Patients with indeterminate results should be tested with another sample taken 1-2 weeks after the first, if clinically indicated

Due to high seroprevalence of various community-related infectious diseases in the general Indian population, all results must be interpreted in the context of the total clinical history and supplementary findings of other investigative procedures.

Test method: Enzyme Immuno-Assay


HERPES SIMPLEX VIRUS-1 IgG, SERUM

Herpes simplex virus (HSV) is a widespread human pathogen with a tendency to induce lifelong latency in the sensory nerve ganglia, following the primary infection. Recurrent HSV infections are common due to endogenous reactivation of the virus .Precipitating factors for recurrence can include exposure to sunlight, fever, local trauma, trigeminal nerve manipulation, menstruation and emotional stress. HSV-1 and HSV-2 are 2 serologically distinguishable types. HSV 1 is primarily transmitted by contact with oral secretions and is usually associated with oral infections and lesions above the waist. HSV 2, on the other hand, is primarily transmitted by contact with genital secretions and is associated with genital infections and lesions below the waist. However the correlation between HSV type and the location of the lesion is not absolute. Transmission can occur from overtly infected persons as well as asymptomatic excretors. HSV is known to cause severe generalized and fatal infections in newborns and immunocompromised people.

Pregnant women who develop genital herpes are two to three times more likely to have spontaneous abortions or deliver a premature infant than are pregnant non-infected women. Active virus excretion in genital secretions of pregnant women may result in severe neonatal HSV infection that is associated with high morbidity and mortality rates if untreated.

HSV specific IgM becomes detectable after about one week of infection. Presence of IgM usually indicates recent or active recurrent infection. Specific IgG generally appears two to three weeks after primary infection, but may fall in titer after a few months. Sero-conversion of HSV -Specific IgG from negative to positive also suggests recent or active recurrent infection .However; some patients with recurring disease may not show an increase in titer. Detection of IgG allows assessment of the patient's immune status and provides serological evidence of prior exposure to HSV. Testing paired sera to demonstrate seroconversion is recommended for accurate diagnosis of recent (primary or recurrent) HSV infection.

Due to the strong serological cross-reactivity between HSV-1 and HSV-2, antibodies produced in response to infection by one virus can cross react with the other, though the response to the homologous, i.e., the infection virus is generally greater. For this reason, testing paired acute/convalescent specimens is useful to show change in antibody activity. Patients with indeterminate results should be tested with another sample taken 1-2 weeks after the first, if clinically indicated

Due to high seroprevalence of various community-related infectious diseases in the general Indian population, all results must be interpreted in the context of the total clinical history and supplementary findings of other investigative procedures.

Test method: Enzyme Immuno-Assay


HIGH SENSITIVITY C-REACTIVE PROTEIN

hs-CRP test is useful in identifying those subjects who are at an increased risk for cardiovascular disease and have normal or borderline increased lipid values. A combination of hs-CRP and atherogenic index such as total cholesterol : HDL cholesterol or LDL cholesterol : HDL cholesterol should be taken into consideration to improve risk prediction for cardiovascular disease.
Higher hs-CRP concentrations have been found in smokers, individuals with osteoarthritis and obese individuals. In women, hs-CRP concentrations may be influenced by hormonal status and are elevated in pregnancy.

To establish the baseline hs-CRP levels, specimens are tested 2-3 weeks apart and the average of 2 results is considered as the baseline. If hs-CRP levels are >10 mg/L repeat specimen is taken after I month. If both hs-CRP results are more than 10 mg/L then non-cardiovascular conditions have to be considered.



RAMESH B. DESHPANDE,MD SIMI BHATIA,MD C. S. SOMAN,MD
CONSULTANT PATHOLOGIST HEAD - HISTOPATHOLOGY CONSULTANT ONCOPATHOLOGIST

HIV-1&2 ANTIBODIES, SERUM

Antibodies to HIV-1&2 are detected by Enzyme Immuno-Assay Technique. Since Enzyme Immuno-Assay is a sensitive technique, it is used as a screening test. In a small percentage of cases a false Positivity may occur. Therefore all positive cases by Enzyme Immuno-Assay need to be confirmed by second line, Specific test performed by Western Blot (Immunoblot) Technique.

HIV-1&2 Antibodies test may be Negative upto 6 months after acquisition of HIV infection and this period is designated as a 'Window Period'. In such cases a Negative test may have to be repeated after 6 months to monitor Seroconversion.

Neonates born of HIV infected mothers may have HIV infection or can be uninfected despite the presence of maternal antibodies to HIV in their blood. Such babies should undergo additional testing such as Polymerase Chain Reaction (HIV DNA by PCR: Test No. 9885B) to ascertain their status of infection. All sera are stored frozen for four weeks at SRL Ranbaxy for additional testing.

Test Technique: Microparticle Enzyme Immuno-Assay

SEROLOGY TEST PERFORMED ON ABOTT AXSYM INSTRUMENT


Drug allergens
Allergy or Type I hypersensitivity is an inappropriate immune response mounted by the human body, in response to exposure to certain antigens, also termed as allergens. Development of allergic disease has been associated with heredity and various environmental & health factors. Specific IgE antibodies appears in human serum or plasma as a result of sensitization to a specific allergen and can be detected following exposure. The development of symptoms is a result of complex interactions between allergens, IgE antibodies, other parts of the immune system and other factors that influence the response in the various target organs. Symptoms of allergy vary in complexity, severity and organ manifestation. Allergic diseases generally begin in childhood, although they can arise at any age. Specific IgE antibodies often precede symptoms in childhood, but the clinical symptoms seem to catch up with time
Local and acute systemic reactions to exogenous human insulin have occasionally been reported . Patients treated exclusively with human insulins sometimes develop anti-insulin antibodies of the IgG and IgE class, however in very low titers . Allergic symptoms to human insulin have been found in <1% of de novo-treated patients.
Test:
The ImmunoCAP Specific IgE is an in-vitro test, that measures the concentration of circulating, allergen-specific IgE antibodies in human serum or plasma .It provides an objective measurement of the sensitization to the allergen, thus helping to diagnose or predict the risk of IgE mediated allergic disorders and guide clinical decisions.
Scoring Table:
Class Concentration(kUA/L) Level Interpretation

0 0.00 - 0.34 Absent Look for non allergic causes of disease
I 0.35 - 0.69 Low Uncertain clinical significance
II 0.70 - 3.49 Moderate Possibly contributing to total allergy load
III 3.50 - 17.49 High Clinically significant
IV 17.50 - 49.99 Very High Clinically significant
V 50.00 – 100 Very High Clinically significant
VI >100 Very High Clinically significant
Notes:
• For drug specific IgE determinations, results below limit of quantitation indicate the absence of specific IgE antibodies to the specific drug and non sensitivity .However, such results can also be found in patients hypersensitive to drugs,eg when
1) the symptoms are mediated without IgE involvement ,
2) the blood sample has been collected a long time after the latest adverse reaction of a therapeutic treatment procedure. It has been shown that the concentration of IgE antibodies decreases with time after the allergic reaction,
3) the blood has been collected very soon after the allergic reaction. An interval between the time of the allergic reaction and the appearance of measurable specific IgE antibodies has been observed occasionally.
Hence blood for drug testing should ideally be collected no sooner than 2 to 3 weeks and no later than 6 months after drug exposure.
• Identical results for different allergens may not be associated with clinically equivalent manifestations, due to differences in patient sensitivities.
• Crossreactivity between human insulin and pancreatic insulin of animal origin has been reported. Hence a definitive clinical diagnosis should not be based on the results of any single diagnostic in-vitro method, but should only be made by the physician after all clinical and laboratory findings have been evaluated.

Test Technique: Fluorescent Enzyme Immunoassay.


INSULIN LIKE GROWTH FACTOR - I, SERUM

Insulin like growth factor-I is a single polypeptide chain with three intra-molecule disulphide bonds. It is structurally homologous to IGF-II and insulin. Production of IGF-I, also known as Somatomedin C, is growth hormone (GH) dependent. The liver is the main source of circulating IGF-I and its synthesis is regulated by GH.

In humans’ serum IGF-1 level are low during foetal and neonatal life, increase gradually during puberty, peaking at tanner stages 3-4, and show a decline similar to GH with ageing. In females at each age, average IGF-1 plasma levels are slightly higher than in males. IGF measurement has been advocated as a screening and management tool in growth hormone deficient children. Its use in diagnosis along with growth hormone measurements or as a tool to assess a child's response to administered growth hormone has led to prominent place in the endocrine laboratory, particularly when dealing with growth disorders. A second major use of IGF-1 measurement is in the diagnosis and treatment of acromegaly. IGF-1 levels may be helpful to assess the results of bromocryptine treatment of acromegaly.

Test method: Enzyme Immunoassay.


INSULIN, SERUM

Insulin is protein hormone that is synthesized, stored and secreted by the beta cells located in the islets of Langerhans in the pancreas. Insulin is responsible for regulating glucose concentrations in the blood. Initially in the beta cells, insulin exists as a large molecule called preproinsulin. Preproinsulin is a single-chain precursor consisting of 110 amino acids. A chain of 24 amino acids of preproinsuiln is cleaved forming proinsulin, the precursor of insulin and C-peptide.

Proinsulin consists of two amino acids chains of insulin connected by disulfide bonds and a connective peptide, called C-peptide. The alpha (A) chain of insulin consists of 21 amino acids, the beta (B) chain of insulin consists of 30 amino acids, and C-peptide consists of 31 amino acids. Proinsulin is stored in the secretory granules in the Golgi apparatus of the beta cells until proinsulin undergoes proteolysis to form insulin and C-peptide. At the cell membrane, insulin and C-peptide are released into the portal circulation in equimolar amounts.

Insulin is released in response to the presence of glucose in the blood typically after the ingestion of a meal. A normal healthy individual produces 40 to 50 units of insulin each day. The half-life of insulin in serum or plasma is 5 to 10 minutes. Approximately 50% of the insulin released into the portal circulation is cleared by the liver. Insulin binds to receptor cells located on cell membranes of target tissues. The target tissues are primarily liver, fat, and muscle tissue. Insulin modulates glucose concentration in the blood by stimulating glucose uptake (Glycogenesis) in muscle, Lipogenesis in Adipose tissue and inhibiting Glycogenolysis and Gluconeogenesis in the liver.

If insulin production is not stimulated, blood glucose levels will not be lowered and hyperglycemia results. Fasting hyperglycemia supports the diagnosis of diabetes mellitus. There are two types of diabetes mellitus: type I or insulin-dependent diabetes mellitus (IDDM) and type II or non-insulin-dependent diabetes mellitus (NIDDM). Insulin therapy is used for insulin-dependent diabetes mellitus (IDDM) patients and many non-insulin-dependent diabetes mellitus (NIDDM) patients. In type I diabetes (IDDM) there is a deficiency of insulin. This can be the result of autoimmune destruction of the beta cells or the presence of autoantibodies to insulin. Many factors can play a role in the development of Type II diabetes (NIDDM). Type II diabetes (NIDDM) can result if there is a decreased biological response to circulating insulin (insulin resistance) or if there is decreased or diminished insulin secretion due to beta cell failure.

Insulin levels are not typically used in the diagnosis or management of diabetic patients. Insulin levels can be useful in evaluating patients with fasting hypoglycemia, in determining insulin resistance in the general population, and in assessing abnormalities in beta cell secretory function. Insulin levels are used in studying the pathophysiology of diabetes.

Heterophilic antibodies in human serum can react with reagent immunoglobulins, interfering with in vitro immunoassays. Patients routinely exposed to animals or to animal serum products can be prone to this interference and anomalous values may be observed. Additional information may be required for diagnosis.

Test method: Chemiluminescence


IONISED CALCIUM, SERUM


Test method: Ion Selective Electrode


LEUKEMIA TRANSLOCATIONS - PANEL 6
Clinical Utility

• This panel detects following four translocations : t(1; 19) (q23; p13), t(9; 22) (q34; q11), t(4;11) (q21; q23) and t(12; 21) (p13; q22),
• Characterization of fusion gene transcripts in leukemia that result from chromosome translocations provides valuable information regarding appropriate treatment and prognosis.
• It provides prognostic information for AML as well as ALL patients i.e.
• Detection of t(12; 21) (p13; q22), in AML-M2 indicates excellent prognosis
• Detection of t(1; 19) (q23; p13), in ALL patients indicates poor prognosis.
• Detection of t(9; 22) (q34; q11), in AML and ALL patients indicates poor prognosis.
• Detection of t(4;11) (q21; q23), in ALL infant patients indicates very poor prognosis.

Method:
Multiplex RT-PCR

Interpretation:
The presence of a particular size amplimer in the given panel indicates the presence of that translocation. Absence of any amplimer indicates the absence of the given translocation or gene rearrangement in the sample.

Limitations:
• PCR is a highly sensitive technique; common reasons for paradoxical results are contamination during specimen collection, selection of inappropriate specimens and inherent PCR inhibitors in the specimen.
• Absence of translocation in a panel does not rule out the presence of translocations other than the ones mentioned in the panel.

References:
• Blood,Vol 92, No. 2 , 1998: pp 574-588
• Blood, Vol 97, No. 31, 2001: pp 805-808
• Indian Pediatrics 2003; 40:1191-1194


LEUKEMIA TRANSLOCATIONS - PANEL 1


Clinical utility of Molecular genetic testing:
--This panel detects following seven translocations :
t(1; 19) (q23; p13), Inv 16 (p13; q22), t(9; 22) (q34; q11), t(4;11) (q21; q23),
t(12; 21) (p13; q22), t(15; 17) (q21; q22), t(8;21) (q22; q22)

--Characterization of fusion gene transcripts in leukemia that result from chromosome translocations provides valuable information regarding appropriate treatment and prognosis.
--It provides prognostic information for AML as well as ALL patients i.e.
--Detection of t(15; 17) (q21; q22) in AML-M3 patients indicates good prognosis.
--Detection of Inv 16 (p13; q22) in AML-M4 patients indicates good prognosis.
--Detection of t(8; 21) (q22; q22) in AML-M2 patients indicates good prognosis.
--Detection of t(12; 21) (p13; q22), in AML-M2 indicates excellent prognosis
--Detection of t(1; 19) (q23; p13), in ALL patients indicates poor prognosis.
--Detection of t(9; 22) (q34; q11), in AML and ALL patients indicates poor prognosis.
--Detection of t(4;11) (q21; q23), in ALL infant patients indicates very poor prognosis.

Method:
Multiplex Reverse Transcriptase PCR

Interpretation:
The presence of a specific size amplimer in the given panel indicates the presence of respective translocation. Absence of any amplimer indicates the absence of the given translocation or gene rearrangement in the specimen analysed.

Limitations:
-PCR is a highly sensitive technique; common reasons for paradoxical results are contamination during specimen collection, selection of inappropriate specimens and inherent PCR inhibitors in the specimen.
-Absence of translocation in a panel does not rule out the presence of translocations other than the ones mentioned in the panel.
-Samples must be received in the lab within 48 hrs of collection. Specimen processing after 48 hrs of collection may lead to erroneous results due to labile nature of RNA

"This test is developed and validated at SRL Ranbaxy Ltd. Due to limited population specific data, currently this test is meant for research use only".

References:
1. Blood,Vol 92, No. 2 , 1998: pp 574-588
2. Blood, Vol 97, No. 31, 2001: pp 805-808
3. Indian Pediatrics 2003; 40:1191-1194


LEUKEMIA TRANSLOCATIONS-PANEL 2

Clinical Utility:
--This panel targets following three translocations:
t(15; 17) (q21; q22), Inv 16 (p13; q22), t(8; 21) (q22; q22)

--Characterization of fusion gene transcripts in leukemia that result from chromosome translocations provides valuable information for appropriate treatment descisions and prognosis.
--It provides prognostic information for AML patients i.e.
--Detection of t(15; 17) (q21; q22) in AML-M3 patients indicates good prognosis.
--Detection of Inv 16 (p13; q22) in AML-M4 patients indicates good prognosis.
--Detection of t(8; 21) (q22; q22) in AML-M2 patients indicates good prognosis.

Method:
Multiplex Reverse Transcriptase PCR

Interpretation:
The presence of a particular size amplimer in the given panel indicates the presence of the respective translocation. Absence of any amplimer indicates the absence of the given translocation or gene rearrangement in the specimen analysed.

Limitations:
--PCR is a highly sensitive technique; common reasons for paradoxical results are contamination during specimen collection, selection of inappropriate specimens and inherent PCR inhibitors in the specimen.
--Absence of translocation in a panel does not rule out the presence of translocations other than the ones mentioned in the panel.
--Samples must be received in the lab within 48 hrs of collection. Specimen processing after 48 hrs of collection may lead to erroneous results due to labile nature of RNA.

"This test is developed and validated at SRL Ranbaxy Ltd. Due to limited population specific data, currently this test is meant for research use only".

References:
1.Blood,Vol 92, No. 2 , 1998: pp 574-588
2.Blood, Vol 97, No. 31, 2001: pp 805-808
3.Indian Pediatrics 2003; 40:1191-1194


LEUKEMIA TRANSLOCATIONS-PANEL 3
Clinical Utility:
--This panel targets following eleven different translocations. in MLL gene:
t(1;11) (p32; q23), t(1;11) (p21; q23), t(4; 11) (q21; q23), t(6;11) (q27; q23),
t(9;11)(p22;q23), t(10;11)(p12;q23), Dup MLL (11q23), t(11; 17) (q23; q21), t(11; 19) (q23; p13.1), t(11; 19) (q23; p13.3), t(X;11) (q13; q23)
--Characterization of fusion gene transcripts in leukemia that result from chromosome translocations provides valuable information regarding appropriate treatment and prognosis.
--MLL gene rearrangements are associated with an extremely poor prognosis in Acute Lymphoblastic Leukemia (ALL); particularly infant ALL

Method:
Multiplex Reverse Transcriptase PCR

Interpretation:
The presence of a specific size amplimer in the given panel indicates the presence of the respective translocation. Absence of any amplimer indicates the absence of the given translocation or gene rearrangement in the specimen analysed..

Limitations:
--PCR is a highly sensitive technique; common reasons for paradoxical results are contamination during specimen collection, selection of inappropriate specimens and inherent PCR inhibitors in the specimen.
--Absence of translocation in a panel does not rule out the presence of translocations other than the ones mentioned in the panel.
--Samples must be received in the lab within 48 hrs of collection. Specimen processing after 48 hrs of collection may lead to erroneous results due to labile nature of RNA.

"This test is developed and validated at SRL Ranbaxy Ltd. Due to limited population specific data, currently this test is meant for research use only".

References:
1.Blood,Vol 92, No. 2 , 1998: pp 574-588
2.Blood, Vol 97, No. 31, 2001: pp 805-808
3.Indian Pediatrics 2003; 40:1191-1194


Leukemia Translocation Panel 4

Clinical utility of Molecular genetic testing:
--This panel detects following six translocations :
t(1; 19) (q23; p13), t(9; 22) (q34; q11), t(4;11) (q21; q23), t(1;11) (p32; q23), t(11;
19) (q23; p13.3), t(X;11) (q13; q23)
--Characterization of fusion gene transcripts in leukemia that result from chromosome translocations provides valuable information regarding appropriate treatment and prognosis.
--Presence of any of these six translocations indicates poor prognosis for the ALL patients.


Method:
Multiplex Reverse Transcriptase PCR

Interpretation:
The presence of a specific size amplimer in the given panel indicates the presence of the respective translocation. Absence of any amplimer indicates the absence of the given translocation or gene rearrangement in the specimen analysed..

Limitations:
--PCR is a highly sensitive technique; common reasons for paradoxical results are contamination during specimen collection, selection of inappropriate specimens and inherent PCR inhibitors in the specimen.
--Absence of translocation in a panel does not rule out the presence of translocations other than the ones mentioned in the panel.
--Samples must be received in the lab within 48 hrs of collection . Specimen processing after 48 hrs of collection may lead to erroneous results due to labile nature of RNA.


Note :
The test is developed at SRL Ranbaxy Ltd.,and its performance is evaluated at SRL Ranbaxy Ltd., Mumbai.

References:
1.Blood,Vol 92, No. 2 , 1998: pp 574-588
2.Blood, Vol 97, No. 31, 2001: pp 805-808
3.Indian Pediatrics 2003; 40:1191-1194


The clone for “LH" antibody is "LH - C93”.


LH, FSH AND PROLACTIN, SERUM

FSH and LH are Pituitary hormones, useful to distinguish Primary Gonadal Failure from secondary (Hypothalamic/ Pituitary) causes of Gonadal Failure, and Amenorrhea. High values of LH & FSH occur with Castration, Ovarian Failure and in
Post Menopausal State. Excessive LH and FSH are found in Hypogonadism, Gonadal Failure, Testicular Feminization Syndrome & Menopause. LH and FSH is mainly useful in defining menstrual cycle phases in Infertility evaluation of women and Testicular Dysfunction in men. In Pituitary or Hypothalamic Failure both would be low but when one hormone is high & other one is low a Gonadotropin - producing Pituitary Tumor is likely. Elevated basal LH with High LH / FSH ratio in essentially nonovulatory adult female could indicate Stein- Leventhal Syndrome. Prolactin levels may be elevated in Pituitary tumors, Amenorrhea & Polycystic Ovarian Syndrome.

Hormone assay values are to be correlated with the age and clinical status of the patient irrespective of whether the values are appearing in the 'In Range' or 'Out of Range' columns.

Test method: Chemiluminescence.


LIPASE, SERUM

Test Technique: Colorimetric


LIVER FUNCTION PROFILE

Test method:

For Aspartate Aminotransferase, Alanine Aminotransferase, Alkaline Phosphatase, G-Glutamyl Transferase, Lactate Dehydrogenase, Total Bilirubin, Bilrubin Direct, Total Protein, Albumin, Globulin, Albumin/Globulin Ratio: Spectrophotometry


LIVER-KIDNEY-MICRO ABS

Autoimmune liver disease (e.g. autoimmune hepatitis and primary biliary cirrhosis) is characterized by the presence of auto-antibodies including smooth muscle antibodies (SMA), anti-mitochondrial antibodies (AMA), and anti-liver/kidney microsomal antibodies type 1 (anti-LKM-1). Subtypes of autoimmune hepatitis (AIH) are based on autoantibody reactivity patterns.

Anti-LKM-1 antibodies serve as a serologic marker for AIH type 2 and typically occur in the absence of SMA and antinuclear antibodies. Patients with AIH type 2 more often tend to be a young female, and have severe disease that responds well to immunosuppressive therapy.

Serologic tests for auto-antibodies, including anti-LKM-1, should not be relied upon exclusively to determine the etiology or prognosis of patients with liver disease. Anti-LKM-1 antibodies may occur in some patients with chronic hepatitis caused by hepatitis C virus infection. Although the epitopes recognized by anti-LKM-1 antibodies in hepatitis C virus infection are different than in patients with AIH type 2, physician must use caution in interpreting the results of tests for anti-LKM-1 antibodies in such patients.

Test method: Enzyme Immuno-Assay.


LIVORHYTHM-1:

Jaundice or icterus is a classical feature of liver disease.
CBC helps in assessing the presence of anemia, lymphocytosis (generally seen in Viral hepatitis) or polymorphonuclear leukocytosis (indicating acute bacterial infection or the possibility of liver abscess)
A raised ESR accompanying lymphocytosis is further evidence of a viral or tubercular etiology.
CRP an acute phase protein; is indicative of infection and probability of an autoimmune etiology.
In hemolytic anemia, unconjugated and conjugated bilirubin rise without raise in enzyme levels.
In hepatitis (infectious and chemically induced) there is a marked rise in AST, ALT and LDH. Direct and indirect bilirubin rise along with ALP & GGT. However, total protein and albumin remain normal.
In cirrhosis, almost the reverse pattern from that of hepatitis is seen. Thus AST, ALT and LDH levels are normal or low or only mildly elevated. Both indirect and direct bilirubin tend to be elevated. Stones in the biliary tree or neoplasms cause elevations in direct bilirubin, ALP & GGT. Isolated elevations of ALP & LDH are seen in space occupying lesions of liver e.g. Metastatic carcinoma. Passive congestion of liver is characterized by mild elevation of AST, ALT and LDH, Bilirubin and Alkaline phosphatase. Similar pattern is seen in infectious mononucleosis with marked rise in Bilirubin. Acute fulminant hepatic failure appears as a combination of hepatitis and cirrhosis. AST and ALT are exceptionally high whereas Total Proteins and Albumin are markedly reduced. LDH, ALP and bilirubin are also elevated. A disproportional rise of AST over ALT, further confirms the diagnosis.
The
Australia antigen (HbsAg) confirms the HBV infection. However, seroconversion (i.e., transition from Hepatitis B surface antigen positivity to Hepatitis B surface antibody positivity) will cause the antigen to become undetectable in the serum, leading to a false belief of a negative evidence of HBV infection. Further HBV markers are indicated after one of these (HbsAg or HbsAb) is recorded as Positive.
Hepatitis A IgM and Hepatitis E IgM Antibodies are raised in the acute (early) phase of these fecoorally transmitted viral hepatitis infections, respectively.
Detection of HCV antibodies confirms the infection with Hepatitis C virus, following a window period of 5 to 8 weeks.
Leptospira icterohaemorrhagiae is the causative agent of the classic Weil's disease, severely affecting the liver, and often, the kidneys. The motile Leptospira can be easily detected in urine samples of affected patients but this becomes rapidly negative if any antibacterial treatment is started or in cases that are past the "acute" phase. Hence, detection of leptospira IgM and IgG antibodies confirm the etiology, either a raised IgM alone, or a disappearing IgM with a greatly raised IgG level.
Detection of Malarial Antibodies(IgG) is evidence of a malarial etiology as both Plasmodium vivax and falciparum, the cause of malaria in
India, have a hepatic phase prior to infection of the RBCs. At this stage of the infection, malarial parasites might or might not be detectable in the peripheral smear.
Detection of E.histolytica in the stool sample of the patient corroborates a diagnosis of amoebic hepatitis/amoebic liver abscess although this is not the rule.
If all the confirmatory tests yield no conclusive evidence, the probability of autoimmune hepatitis malignancy (either a primary or metastatic) or the presence of less common viral agents or other infections must be considered. The ordering of SRL's panels for these - LIVER DISORDER-2, LIVER DISORDER-3 OR LIVER DISORDER-4 would confirm any of these etiologies. The ordering of any of these panels would depend upon clinical history and presentation, as well as results of other supportive investigations (radio-imaging, ultra-sonography, scans, etc.).


LIVORHYTHM-2, SERUM

Lesions seen radiologically in the liver need to be differentiated as benign or malignant. These lesions can be solitary or multiple, with the etiological agent being a parasite, virus or carcinoma.

The tests for detection of EBV (Nuclear Antigen) IgG and IgM antibodies rules out infectious mononucleosis as a cause of viral hepatitis.

Serology for antibodies to Entamoeba histolytica is a useful adjunctive test for diagnosis of amoebic hepatitis or hepatic amoebic abscess. The absence of serum antibodies to
E. Histolytica after 1 week of symptoms is strong evidence against the diagnosis of invasive amoebiasis. E. Histolytica antibodies are detected in 90-95 percent of patients with amoebic liver disease.

The Serodiagnostic assay for Echinococcus granulosus is useful for detection of antibody to the specific echinococcal antigen.

Alpha fetoprotein is a useful marker for diagnosing hepatocellular carcinoma. Marked increase in AFP levels is seen in cases of hepatocellular carcinoma although high levels may also be documented in benign hepatic conditions such as acute viral hepatitis, chronic active hepatitis and cirrhosis.

Both Hepatitis B Virus and Hepatitis C Virus are known to be associated with cirrhosis and hepatocellular carcinoma, these being the complications of chronic active hepatitis caused by these two viruses (HBV - 16-25%; HCV - 25-40%). In this situation, the inclusion of HCV 4, a combination of HCV RT-PCR with a 3rd generation anti-HCV ELISA, helps to confirm Hepatitis C Virus as the etiological factor of hepatocellular carcinoma. The result needs to be correlated for etiological factor of hepatocellular carcinoma. (For HCV/4 refer SRL #7516).

Keeping in view that the evaluation of Hepatitis B Virus infection has already been carried out (as in Liver Disorder I), there is no obvious need to reassess for HBV markers. If clinical suspicion still prevails, an additional test for HBV DNA Qualitative (SRL #8141) could be ordered.

Methodology :

Alpha IgG Antibodies - Enzyme Immunoassay
Entamoeba Histolytica IgG Antibodies - Enzyme Immunoassay
Epstein-Barr Virus (Nuclear Antigen) IgM & IgG Antibodies - Enzyme Immunoassay


LIVORHYTHM-3

1. Liver disease due to non-hepatotropic viruses such as Cytomegalovirus (CMV), Epstein-Barr Virus (EBV), Herpes Simplex Virus (HSV) and Varicella-Zoster Virus (VZV) may share certain clinical features with hepatitis caused by the primary group of hepatitis causing viruses.

2. Toxoplasmosis is recognized both as a neonatal infection and as an acquired infection in children and adults. Acquired infections are usually asymptomatic and occur due to dissemination of the parasite through the blood stream, localising in organs such as the liver, leading to its injury and enlargement.

3. Serological tests for IgG and IgM antibodies for these agents are mandatory in the differential diagnosis. Serological tests are helpful when they are Negative or show a rising titer of IgG and IgM antibodies for diagnosis of specific viruses.

4. Although the presence of IgM anitbodies specific for a particular etiologic agent, as a general rule, indicate current/acute infection with that organism, no specific IgM antibodies might be detectable in the following situations;
a. Infection past the "Acute Phase", thereby resulting in IgM levels that have come back to insignificant levels.
b. Secondary infection, i.e., a second or subsequent exposure to the same etiologic agent, in which case the immune system does not mount a primary immune response (IgM Abs)
c. Chronic infection with that agent, resulting in absent IgM and a sustained rise in IgG Abs.

In all these instances, the IgG levels are likely to be high and a repeat assay of the same will give evidence of a rising or falling titer.

5. The parasite of Kalazar, Leishmania donovani, is an important cause of hepatosplenomegaly. A microscopic examination of a stained blood film is often successful in demonstrating the presence of amastigote forms ( LD bodies) of the parasite in the peripheral blood. (For confirmation of the same, a stained Bone marrow smear can be examined SRL #1054)

6. Histopathology, CMV PCR & HSV PCR in relevant cases will provide supportive evidence to the diagnosis. For the above 3 investigations, please refer to the following SRL Test codes:

SRL # 1505 - Histopathology (Liver Core Biopsy)
SRL # 7575 - CMV DNA PCR
SRL # 7581 - HSV DNA PCR


LIVORHYTHM-4


Tissue diagnosis with special stains by obtaining a C-T guided liver biopsy helps in identifying the presence of caseating granulomas and cirrhosis. Special stains, including Ziehl-Neelsen's and reticulin stains, help in detecting AFB and reticulin, respectively. Detection of reticulin is important in the diagnosis of cirrhosis.

In the absence of caseous necrosis in the epithelioid granulomas, Myco3 (TB PCR with radiometric mycobacterial culture) is helpful in diagnosis of tuberculous infection of the liver. Further, as non-caseating epithelioid granulomas are seen in both tuberculosis and sarcoidosis, a Positive result of TB PCR would differentiate between the two. In the event of the Mycobacterial culture yielding Positive results, the mycobacterial isolate can then be subjected to antimycobacterial drug susceptibility tests. (SRL # 1464R2, 1464R1, 1490, 5649), if needed, to ascertain the correctness of the instituted time of therapy.

Both Hepatitis B virus and Hepatitis C virus are etiological agents causing cirrhosis, which is a complication of chronic active Hepatitis. ELISA tests for these two viral infections in the initial stages as well as in cases of very long standing duration, can be Negative. Evaluation of HBV & HCV by PCR will help in determining the etiology in such cases.

Malaria Antibodies – Rapid Test

Malaria is caused by the protozoan parasites Plasmodium falciparum, P. vivax, P. ovale, and P. malariae, and is transmitted by a species of the female Anopheles mosquito. It is usually suspected based on the patient's symptoms and the physical findings at examination. However, for a definitive diagnosis detection of malaria parasites or their components (i.e. antigens) is most essential. Serologic testing for Malaria antibodies is not routinely used for diagnosis of acute malaria. Antibodies test may be useful for following conditions:
- Screening blood donors involved in cases of transfusion-induced malaria when the donor's parasitemia may be below the detectable level of blood film examination
- Screening patients with a febrile illness who is suspected of having malaria and from whom repeated blood smears are negative.
- Screening patients who have been recently treated for malaria but in whom the diagnosis is questioned.
Usually parasitemia precedes antibodies production. For P. vivax antibodies appear
within 2-6 days of parasitemia, whereas for P. falciparum antibodies appear within 4-6
days of parasitemia. If parasitemia is suppressed by treatment, antibodies are detectable
early.
It is a rapid qualitative method for detection of antibodies of all isotypes (IgG, IgM and IgA) specific to Plasmodium falciparum and Plasmodium vivax simultaneously in whole blood specimens. This test can be used for initial screening of malaria and it is recommended to confirm all positive specimens by microscopy.

References :
1. Br Med J, 1980;280:1575-1576.
2. MMWR 2005;54:25-39.
3. Vox Sang 2004;87:150-155.
4. Clin Microbiol Rev 2002;15:66-78.


MALARIA ANTIGEN DETECTION, BLOOD


Four species of the plasmodium parasites are responsible for human malaria infections; P. falciparum, P. vivax, P. ovale and P. malariae. P. falciparum and P. vivax are the most prevalent. Early detection and differentiation of malaria is of paramount importance due to incidence of cerebral malaria and drug resistance associated with P. falciparum malaria causing most of the morbidity and mortality worldwide .As treatment depends on the species, differential diagnosis of P. falciparum and P. vivax is extremely important for better patient care management and faster recovery.
The current test is a qualitative test for detection of the P. falciparum specific histidine rich protein-2 (Pf. HRP-2) and P. vivax specific lactate dehydrogenase (pLDH) in whole blood samples. The assay offers an advantage over other commercially available antigen detection assays as it is able to detect and distinguish P. vivax and P. falciparum infections and also identify mixed infections.
In case of a suspected P. falciparum case, a positive band for Pf. HRP-2 is highly predictive of infection, but a negative test result may not rule out the same. This may be seen in patients with a very low parasitic index (<5 parasites/HPF), as the test sensitivity and test band intensity correlated directly with the parasite density. A false negative result may also be obtained in carriers, as Pf. HRP-2 is not secreted in the gametogony (sexual) stage. Rarely, a false negative result may be seen in individuals with a gene deletion for the production of HRP-2.
It is important to note that Pf. HRP-2 is known to persist after successful therapy and may be detectable even after the clinical symptoms of malaria have disappeared and the parasites have apparently been cleared from the host. Hence it should not be used for monitoring early therapeutic responses.
In case of a stand alone P. vivax infection, the band for pLDH may be used to monitor patient progress during therapy and predict recrudescence and possible drug-resistant infections. In case the pLDH band remains positive with the same intensity after 5-10 days, the possibility of a resistant strain has to be considered. A negative pLDH result does not rule out P. vivax infection, as may be seen in patients with a very low parasitic index (<5 parasites/HPF).
Since the test detects P. falciparum specific HRP-2 and P. vivax specific LDH, a negative test result does not rule out infection with P. ovale and P. malariae.
Constant exposure to the malarial parasites, as seen in areas of high endemicity, may result in positive results with doubtful clinical significance. Hence, the results must always be correlated with clinical history and relevant epidemiological and therapeutic context. Also note that blood film examination remains the standard method for diagnosing malaria, since it detects all Plasmodium spp. and allows visualization of parasite growth stages, which is essential for making therapeutic decisions.

Test method: Immunochromatography Technique


MALARIA PARASITE, BLOOD/ SMEAR

Malaria is an acute and sometimes a chronic infestation of red blood cells by parasites of the genus, Plasmodium. Malaria is characterized clinically by fever, anemia and splenomegaly. Demonstration of these parasites in the blood smear establishes the diagnosis of malaria. The four species of plasmodia causing human malaria are P. vivax, P. falciparum, P. malariae and P. ovale. Each one of these has typical morphologic features which help in their identification.

Peripheral blood smear examination for detection of malaria parasite is highly specific but is less sensitive (~85%). Malaria parasite may not be detected on peripheral blood smear if infestation rate is very low.

Test method: Microscopy


MICROALBUMINURIA, URINE

Test Technique: Immunoturbidimetry

MYCOBACTERIA IgA, SERUM

Tubercular infection produces IgG, IgM and IgA antibodies. These need to be correlated with clinical and radiological findings. Type of and titre of various antibodies help in determining occurrence and extent of the disease.

IgA antibodies strengthen the diagnosis in cases of suspected Meningitis, Pleuritis and Pericarditis, Renal tuberculosis and AIDS.

Please note: In TB endemic countries like
India, Immunological diagnosis must be made with caution.

Reference: Steingart KR, Henry M, Laal S et al. Commercial Serological Antibody Detection Tests for the Diagnosis of Pulmonary Tuberculosis. A Systematic Review. PLoS Med4(6) 2007: e202.doi:10.1371/journal.pmed.0040202.

Test method: Enzyme Immuno-Assay.

MYCOBACTERIA IgG, SERUM

Tubercular infection produces IgG, IgM and IgA antibodies. These need to be correlated with clinical and radiological findings. Type of and titer of various antibodies help in determining occurrence and extent of the disease.

The results must not be used as the sole criterion for diagnosis because most serological methods like EIA are retrospective indicators of infection by detecting specific IgG antibodies. Results must be interpreted in the context of the total clinical history and evaluated as supplementary information in correlation with findings of other investigative procedures.

In the general Indian population past overt infections and sub-clinical infections greatly contribute to sero- positivity for various community-related infectious diseases.

Please note: In TB endemic countries like
India, Immunological diagnosis must be made with caution.

Reference: Steingart KR, Henry M, Laal S et al. Commercial Serological Antibody Detection Tests for the Diagnosis of Pulmonary Tuberculosis. A Systematic Review. PLoS Med4(6) 2007: e202.doi:10.1371/journal.pmed.0040202.

Test method: Enzyme Immuno-Assay.

MYCOBACTERIA IgM, SERUM

Mycobacterial infection produces IgG, IgM and IgA antibodies. In conjunction with clinical and radiological findings, detection of the type and titre of these antibodies in patients help in determining occurrence and extent of the disease.IgM seropositivity is very frequent but transient. The IgM antibodies are superior to IgG to detect mycobacterial colonization in AIDS patients. IgM plus IgG measurements are analyzed together to detect reactivation cases in chronic infection

Presence of Rheumatoid factor (RF) in the patient specimen can result in false positive as well as false negative IgM results. RF are auto antibodies (anti-IgG) mainly of IgM class and are detected in serum of 5 % of healthy individuals. RF preferably binds IgG immune complexes, resulting in assay interference, thus causing a false positive IgM result. Furthermore, it is also possible that weak binding IgM antibodies are displaced by stronger binding IgG antibodies ,resulting in a false negative result.For this purpose, all specimens tested for Mycobacteria IgM are pretreated with an RF absorbent to eliminate the formation of immune complexes by RF antibodies.

Inapparent subclinical or abortive infections due to mycobacteria are very frequent in the general Indian population due to high endemicity. Hence TB antibody results must not be used as the sole criterion for diagnosis and must be interpreted in the context of the total clinical history and findings of other investigative procedures. IgM antibodies are frequently observed after a contact inherent to professional occupations (eg. Hospital personnel, policemen social workers) or to adverse social conditions. IgM positivity may be observed among babies and infants growing in unhealthy conditions. This positivity usually disappears after 1 to 2 months, provided the subject is no longer in contact with the infectious focus. A transient IgM response may also be observed 7 to 10 days after a Mantoux test.

Test method: Enzyme Immuno-Assay.


PAPANICOLAOU SMEAR

Test method: Microscopy


PAPANICOLAOU SMEAR

Test Method: Microscopy


PARATHYROID HORMONE, SERUM

Parathyroid hormone (PTH) produced by the parathyroid gland is the major circulating factor regulating extra cellular calcium concentration.

The intact PTH peptide (MW~9425) consists of 84 amino acids that are sequenced and designated according to reactivity. The N-terminal or amino-terminal 1-34 region of the intact PTH molecule is biologically active. This region of the molecule contains the amino acid sequence that enables PTH to bind to the parathyroid hormone receptors in target tissues and regulate extra cellular calcium concentrations. The middle and carboxy terminal 35-84 region of the intact PTH molecule is biologically inert but possesses immunological reactivity.

Quantification of circulating intact PTH assists in the differential diagnosis of hypercalecmia. In conjunction with the measurement of ionized calcium, intact PTH evaluations can be used to distinguish between patients with hypoparathyroidism, hypoparathyroidism or hypercalcemia of malignancy.

The diagnosis of primary hyperparathyroidism, a common cause of hyper calcemia is confirmed by elevated ionized calcium concentrations and elevated parathyroid hormone concentrations. Intact PTH levels are also used to assess and manage other metabolic bone disorders including osteoporosis and renal osteodystrophy. The measurement of intact PTH using two site immunoassays provides a more accurate assessment of parathyroid tissue secretary status, especially in patients with renal impairment.

Interpretation of intact PTH values should always take into account serum Calcium results and inter-relationship between these two elements in various disorders involving PTH & Calcium. It is recommended that the intact PTH results should always be interpreted with caution & with consideration of the overall manifestations even when used in conjunction with calcium values.

Measurement of intact PTH is useful in differentiation between hypercalcemia due to hyperparathyroidism & hypercalcemia of malignancy. However the assay is not intended as and should not be relied upon as a diagnostic indicator of malignancy.

Heterophilic antibodies in human serum can react with reagent immunoglobulins, interfering with in vitro immunoassays. Patients routinely exposed to animals or to animal serum products can be prone to this interference and anomalous values may be observed. Additional information may be required for diagnosis.

Test method: Chemiluminescence.


PERIPHERAL SMEAR EXAM, BLOOD

Test method: Microscopy


PHOSPHORUS, SERUM

Test Technique: Phosphomolybdate


PLATELET COUNT, BLOOD

Test method: Automated hematology analyzer alongwith microscopy of smears.


POTASSIUM, SERUM

Test method: ISE (Ion selective electrode)

POTASSIUM, URINE

Test method: ISE (Ion selective electrode)


PREGNANCY TEST, URINE

Human chorionic gonadotropin (hCG) is produced by the developing placenta shortly after fertilization in normal pregnancy.
The hCG one step pregnancy test device (urine) is a rapid chromatographic immunoassay for the qualitative detection of human chorionic gonadotropin in urine to aid in the early detection of pregnancy.

Negative results are expected in healthy non-pregnant women and healthy men. Healthy pregnant women have hCG present in their urine specimen. The hCG one step pregnancy test device (urine) is a rapid test that qualitatively detects the presences of hCG in urine specimen at the sensitivity of 25 mIU/mL.

This test provides a presumptive diagnosis for pregnancy. A confirmed pregnancy diagnosis should only be made by a physician after all clinical and laboratory findings have been evaluated.

Test Technique: Chromatographic Immunoassay


The clone for “PGR” antibody is “SP2 – PGR


PROGESTERONE, SERUM

Progesterone, in conjunction with estrogens, regulates reproductive tract functions during the menstrual cycle. Progesterone is critical in preparing the endometrium for blastocyst implantation and the maintenance of pregnancy.

The major sources of progesterone are the corpus luteum and the placenta in women. Minor sources of progesterone are the adrenal cortex in men and women, and the testes in men.

Progesterone levels are low during the follicular phase of the menstrual cycle. After ovulation, progesterone production by the corpus luteum increases rapidly, reaching a maximum concentration 4 to 7 days after ovulation. These levels are maintained for 4 to 6 days then fall to baseline levels, inducing menstruation.

During pregnancy, progesterone levels rise steadily to their highest levels in the third trimester.
Reference ranges for Pregnant Females:
First Trimester: 11.22 - 90.00
Second Trimester: 25.55 - 89.40
Third Trimester: 48.40 - 422.50

Clinical evaluation of progesterone confirms ovulation and normal luteal function in nonpregnant women. Inadequate progesterone production by the corpus luteum may indicate luteal phase deficiency (LPD), which is associated with infertility and early miscarriage. Women using oral contraceptives have suppressed progesterone level.

Heterophilic antibodies in human serum can react with reagent immunoglobulins, interfering with in vitro immunoassays. Patients routinely exposed to animals or to animal serum products can be prone to this interference and anomalous values may be observed.

Hormone assay values are to be correlated with the age and clinical status of the patient irrespective of whether the values are appearing in the 'In Range' or 'Out of Range' columns.

Test method: Chemiluminescence.


PROLACTIN, SERUM

Prolactin is a single-chain polypeptide hormone secreted by the anterior pituitary under the control of Prolactin-inhibiting factors and Prolactin-releasing factors. These inhibiting and releasing factors are secreted by the hypothalamus. Prolactin is also synthesized by the placenta and is present in the amniotic fluid.

Prolactin initiates and maintains lactation in females. It also plays a role in regulating gonadal function in both males and females. In adults, basal circulating Prolactin is present in concentrations up to 30 ng/mL (636 uIU/mL). During pregnancy and postpartum lactation, serum Prolactin can increase 10 to 20 fold. Exercise, stress and sleep also cause transient increases in Prolactin levels.

Consistently elevated serum Prolactin levels greater than 30 ng/mL (636 uIU/mL) in the absence of pregnancy and postpartum lactation are indicative of hyperprolactinemia, which is the most common hypothalamic-pituitary dysfunction encountered in clinical endocrinology. Hyperprolactinemia often results in galactorrhea, ammenorhea and infertility in females and in impotence and hypogonadism in males. Renal failure, hypothyroidism and Prolactin secreting pituitary adenomas are also common causes of abnormally elevated Prolactin levels. Administration of oral contraceptives can increase Prolactin concentrations.

Heterophilic antibodies in human serum can react with reagent immunoglobulins, interfering with in vitro immunoassays. Patients routinely exposed to animals or to animal serum products can be prone to this interference and anomalous values may be observed. Additional information may be required for diagnosis.

Hormone assay values are to be correlated with the age and clinical status of the patient irrespective of whether the values are appearing in the 'In Range' or 'Out of Range' columns.

Reference Ranges of Prolactin for Pregnant and Post-Menopausal Females are mentioned below:
PREGNANT:
9.7 - 208.5 ng/mL
POSTMENOPAUSAL:
1.8 - 20.3 ng/mL

Test method: Chemiluminescence.


The clone for “PROLACTIN" antibody is “INN-Hprl-3”.


PROTEIN, 24HRS URINE

Test method: Spectrophotometry


PROTEIN, URINE

Test Technique: Pyrogalolred


PROTHROMBIN TIME, PLASMA

Prothrombin Time (PT) is a non-specific indicator of the extrinsic coagulation pathway. PT is expressed as normalized ratio (INR) to improve comparability of results obtain in different laboratories using different thromboplastin reagents. Deficiencies of fibrinogen, prothrombin and factor VII, IX & X result in prolonged PT. Some of the common causes of a prolonged PT are vitamin K deficiency, oral anticoagulant therapy, obstructive liver disease, disseminated intravascular coagulation (DIC), heparin therapy, and malabsorbtion stated leading to vitamin K deficiency.

INR = (patient's PT/mean normal PT) ^ISI
Normal INR: 0.8 - 1.10
Recommended INR for therapy:
INDICATIONS INR
Prophylaxis of venous thrombosis (high-risk surgery)
Treatment of venous thrombosis
Treatment of pulmonary embolism
Prevention of systemic embolism
Tissue heart valves 2.0 - 3.0
AMI (to prevent systemic embolism)*
Valvular heart disease
Atrial fibrillation
Mechanical prosthetic valves (high risk) 2.5 - 3.5
Bilcaflet mechanical valve in aortic position 2.0 - 3.0

* If oral anticoagulant therapy is elected to prevent recurrent myocardial infarction (MI), and INR of 2.5 - 3.5 is recommended, consistent with US Food and Drug Administration recommendations.




Test method: Clotting time based assay

FREE PSA, SERUM

Prostate Specific Antigen (PSA) is a single-chain glycoprotein normally found in the cytoplasm of the epithelial cells lining the acini and ducts of the prostate gland. PSA is detected in the serum of males with normal, benign hyperplastic and malignant prostate tissue and in patients with prostatitis. PSA is not detected (or detected at very low levels) in the serum of males without prostate tissue (because of radical prostatectomy or cystoprostatectomy) or in the serum of most females.

The fact that PSA is unique to prostate tissue makes it a suitable marker for monitoring men with cancer of the prostate. PSA is also useful for determining possible recurrence after therapy when used in conjunction with other diagnostic indices. PSA levels increase in men with cancer of the prostate. After radical prostatectomy PSA levels routinely fall to a very low level, which may not be seen in patients undergoing radiation therapy. Monitoring PSA levels appears to be useful in detecting residual disease and early recurrence of tumor. Therefore, serial PSA levels can help determine the success of prostatectomy and the need for further treatment, such as radiation, endocrine or chemotherapy and in the monitoring of the effectiveness of therapy.

PSA levels should not be interpreted as absolute evidence of the presence or the absence of malignant disease. Before treatment, patients with confirmed prostate carcinoma frequently have levels of PSA within the range observed in healthy individuals. Elevated levels of PSA can be observed in the patients with nonmalignant diseases. Measurement of PSA should always be used in conjunction with other diagnostic procedures, including information from the patient's clinical evaluation. The concentration of total PSA in a given specimen determined with assays from different manufacturers can vary due to differences in assay methods, calibration, and reagent specificity. Values obtained with different assay method cannot be used interchangeably.

Heterophilic antibodies in human serum can react with reagent immunoglobulins, interfering with in vitro immunoassays. Patients routinely exposed to animals or to animal serum products can be prone to this interference and anomalous values may be observed. Specimens for total PSA assay should be obtained before biopsy, prostatectomy or prostatic massage, since manipulation of the prostate gland may lead to elevated PSA levels persisting upto 3 weeks.

FREE PSA


Prostate Specific Antigen exists in serum in three forms namely; (a)PSA enveloped by alpha-2-macroglobulin, (b) PSA complexed to alpha-1-antichymotrypsin (PSA-ACT complex) and (c) Unbound form (Free PSA)

The percentage of free PSA is calculated using results of both assays (Free PSA/ Total PSA). Measurement of total PSA alone may not clearly distinguish between benign prostatic hyperplasia (BPH) from cancer, this is especially true for the total PSA values between 4-10 ng/mL. Patients with prostate cancer generally have a lower percentage of Free PSA than patients with benign prostatic hyperplasia. Percentage Free PSA of more than 15% usually favours benign prostatic hyperplasia. The percentage of Free PSA may also be used to aid in the decision of whether patient should undergo prostatic biopsy.

Test method: Chemiluminescence


CREATININE, SERUM

Creatinine estimation is done to assess kidney function. It is not dependent on dietary factors. Normal values are obtained in kidney diseases, excepting in advanced Renal Failure and therefore its estimation is more valuable if coupled with clearance studies and other Renal Function tests.

Test Technique: Alkaline picrate-kinetic (Jaffe's Kinetic)

BLOOD UREA NITROGEN, SERUM


Urea Nitrogen- a metabolic product of protein metabolism- is affected by diet, systemic blood circulation, renal conditions as also post- renal conditions affecting renal function.

Test Technique: Urease


URIC ACID, SERUM

Test Technique: Uricase


CALCIUM, SERUM

Test Technique: O-cresolphthalein complexone

PHOSPHORUS, SERUM

Test Technique: Phosphomolybdate


CREATININE, SERUM

Creatinine estimation is done to assess kidney function. It is not dependent on dietary factors. Normal values are obtained in kidney diseases, excepting in advanced Renal Failure and therefore its estimation is more valuable if coupled with clearance studies and other Renal Function tests.

Test Technique: Alkaline picrate-kinetic (Jaffe's Kinetic)


RETICULOCYTE COUNT, BLOOD

Reticulocytes are juvenile red cells and contain a reticular (mesh-like) network of RNA and spend about 24 hours in the marrow and spleen before entering the peripheral circulation. They account for 0.5 - 2.5% of the circulating red blood cells in adults. They have high MCV (mean corpuscular volume). The number of reticulocytes is a good indicator of erythropoetic activity, and can be used to monitor the response to treatment of anemia. Decrease in reticulocytes can be attributed to suppression of erythropoiesis due to chemotherapy, aplastic anemia and other hypoproliferative anemias.

An increased number of reticulocytes (reticulocytosis) indicates accelerated erythropoiesis; either as compensation for excessive red cell loss (e.g. haemolysis or bleeding) or, when a marrow starved of iron, vitamin B12 or folate receives the appropriate nutrient.

Test method: Supravital Stain (Microscopy)


RETICULOCYTE PANEL, BLOOD

Reticulocytes are juvenile red cells and contain a reticular (mesh-like) network of RNA and spend about 24 hours in the marrow before entering the peripheral circulation. The account for 0.8 - 2.1% of the circulating red blood cells in adults. They have high MCV (mean corpuscular volume). The number of reticulocytes is a good indicator of erythropoetic activity, and can be used to monitor the progress of treatment of anemia. Reticulocytes increase in number and percentage when there is increased production of red blood cells such as in hemolytic anemia (e.g. sickle cell anemia). Decreases in reticulocytes can be attributed to chemotherapy, aplastic anemia or pernicious anemia.

Clinical utility:
An increased number of reticulocytes (reticulocytosis) indicates accelerated erythropoiesis; either,
· as compensation for excessive red cell loss (e.g. haemolysis or bleeding) or,
· When a marrow starved of iron, vitamin B12 or folate receives the appropriate nutrient
The reticulocyte hemoglobin content is a measure of recent iron incorporation into hemoglobin and is an early indicator of both iron-deficient erythropoiesis and the response to iron therapy. Reticulocyte hemoglobin content is useful as an early measure of functional iron deficiency because the only cells being measured are those recently released from the bone marrow.

Method:
Flow Cytometry on Automated Hematology Analyzer.

References:
1. Blinder MA. Clinical utility of the reticulocyte hemoglobin content in the diagnosis of iron deficiency. Blood. 2003 Jan 1; 101(1): 372-3.
2. Stefano Rapi et al. Reticulocytes and Reticulated Platelets: Simultaneous Measurement in Whole Blood by Flow Cytometry. CCLMFW, vol.36, issue 4, 1998.


RETICULOCYTE PANEL, BLOOD

Reticulocytes are juvenile red cells and contain a reticular (mesh-like) network of RNA and spend about 24 hours in the marrow before entering the peripheral circulation. They account for 0.8 - 2.1% of the circulating red blood cells in adults. They have high MCV (mean corpuscular volume). The number of reticulocytes is a good indicator of erythropoetic activity, and can be used to monitor the progress of treatment of anemia. Reticulocytes increase in number and percentage when there is increased production of red blood cells such as in hemolytic anemia (e.g. sickle cell anemia). Decreases in reticulocytes can be attributed to chemotherapy, aplastic anemia or pernicious anemia.

Clinical utility:
An increased number of reticulocytes (reticulocytosis) indicates accelerated erythropoiesis; either, as compensation for excessive red cell loss (e.g. haemolysis or bleeding) or, when a marrow starved of iron, vitamin B12 or folate receives the appropriate nutrient
The reticulocyte hemoglobin content is a measure of recent iron incorporation into hemoglobin and is an early indicator of both iron-deficient erythropoiesis and the response to iron therapy. Reticulocyte hemoglobin content is useful as an early measure of functional iron deficiency because the only cells being measured are those recently released from the bone marrow.

Test method: Flow Cytometry on Automated Hematology Analyzer


RHEUMATOID FACTOR, SERUM


Rheumatoid factor (RF) latex particle agglutination test is one of the four laboratory test criterions in the diagnosis of probable, definite or classic Rheumatoid arthritis (RA).

Titres less than 8 (or dilution
1:10) are considered within normal range and indicate negative test report. However, negative test report does not rule out RA. A negative test is also seen in osteoarthritis, suppurative arthritis, ankylosing spondylosis and rheumatic fever.

RF test is positive in RA, in more than 50% cases in first six moths of the disease. Positive test results are also observed in a small proportion of healthy individuals, elderly patients above age of 70 years, and in patients of Rheumatoid variants, systemic lupus erythematosus (SLE) and in autoimmune disorders. RF test is positive in 90 per cent individuals with autoimmune disorders like Sjogren's syndrome or cryoglobulinemic purpura. Positive results of RF test are observed in 10 to 40 per cent individuals with chronic infections of bacterial or treponemal or of viral etiology, psoriasis and sarcoidosis.

Test method: Latex Particle Agglutination Method.


ROUTINE COAG PROFILE/PRE-OP PANEL

The initial laboratory study of the patients should be guided by the information obtained from the clinical evaluation. In many cases, however the routine use of a small battery of screening tests has merit because it usually saves time and the results direct the course of further study. It is generally agreed that the most essential information usually can be obtained from the 4 tests (BT, PT, PTT, Platelet count) which in view of their availability, simplicity and low cost are well suitable to save as primary screening test.


Rubella virus, the only member of the Rubivirus genus, causes rubella (also known as german measles),an acute exanthematous infection of children and adults. The clinical illness is characterized by rash, fever and lymphadenopathy and can resemble a mild case of measles. The virus also causes arthralgias and occasional encephalitis.

Infection is particularly disastrous if contracted during the first 4 months of pregnancy. If not immunologically protected, women infected during pregnancy run a high risk of embryo-foetal damage. Congenital rubella causes a wide range of severe defects in the foetus, including cataract, deafness, hepatosplenomegaly, psychomotor retardation, bone alterations, cardiopathies, neuropathies and diabetes.

A positive Rubella IgM result may not always indicate a primary acute infection, as IgM has a tendency to persist, even at high levels, after primary infection. False-positive IgM results may occur due to rheumatoid factor and antinuclear antibodies. Hence, IgG avidity testing is recommended to differentiate between primary infection, IgM persistence and reactivation.

Avidity is defined as the functional binding strength of antibodies to multiple binding sites (epitopes) on the antigen. The test is based on the principle that antibodies formed in response to primary infection have relatively low avidity to the corresponding antigen. With time, a broader antibody response develops with antibodies being formed to more epitopes on the antigen and with a corresponding increase in the antibody antigen avidity. Therefore, when a secondary antibody response occurs with reinfection, it stimulates clonal expansion of memory B cells to a much wider spectrum of epitopes, producing antibodies of considerably greater avidity.

A positive IgM accompanied by low-avidity IgG is suggestive of a primary infection, whereas a high-avidity IgG indicates either IgM persistence or reactivation. A low avidity index may also be seen in a proportion of infected persons for months. Hence it is advised to perform IgM testing initially to point to the need for IgG avidity to avoid misinterpretation of results

Test method: Enzyme Immuno-Assay


RUBELLA IgG & IgM, SERUM

Rubella virus, the only member of the Rubivirus genus, causes rubella (also known as german measles),an acute exanthematous infection of children and adults. The clinical illness is characterized by rash, fever and lymphadenopathy and can resemble a mild case of measles. The virus also causes arthralgias and occasional encephalitis.

Infection is particularly disastrous if contracted during the first 4 months of pregnancy. If not immunologically protected, women infected during pregnancy run a high risk of embryo-foetal damage. Congenital rubella causes a wide range of severe defects in the foetus, including cataract, deafness, hepatosplenomegaly, psychomotor retardation, bone alterations, cardiopathies, neuropathies and diabetes.

Detection of Rubella specific IgM and IgG antibodies is an thus essential tool for diagnosis and follow up of acute infection, assessment of immune status in women of child-bearing age and determination of seroconversion after vaccination.

Rubella specific IgM reaches high levels in serum 2 weeks after the rash and lasts in the circulation for one to two month(s). Specific IgG generally appears a few days after the onset of rash, about 1 week after IgM develops. It rapidly increases to reach a plateau 6 to 10 weeks after the onset of symptoms and then progressively decreases to a level (15-200 IU/mL) lasting for the whole life. Reinfection, completely asymptomatic, is accompanied by moderately increased levels of specific IgG. A four-fold or greater increase in Rubella antibody titre, between acute (8 days after onset of rash) and convalescent sera taken 1-3 weeks apart, is considered diagnostic for acute Rubella infection. Hence paired testing is recommended.

IgG avidity testing is recommended to differentiate between primary infection and reactivation. A positive IgM accompanied by low-avidity IgG is suggestive of a primary infection, whereas a high-avidity IgG indicates either IgM persistence or reactivation. A low avidity index may also be seen in a proportion of infected persons for months. Hence it is advised to perform IgM testing initially to point to the need for IgG avidity to avoid misinterpretation of results.

Seropositivity to Rubella IgG antibodies in all age groups have been reported to be as high as 94% based on premarital serological testing. Hence, all results must be interpreted in the context of the total clinical history and supplementary findings of other investigative procedures.

Test method: Enzyme Immunoassay.

RECOMMENDATIONS:
SRL Ranbaxy Laboratories recommends submission of an early convalescent specimen approximately 1 week after the first (Acute) specimen, if the latter was drawn within 8 days after rash onset. Also submit a late convalescent specimen 2-3 weeks after the acute specimen, if clinically indicated. Please provide the SRL Ranbaxy accession number of the acute specimen with the convalescent specimen.


RUBELLA IgG & IgM, SERUM

Rubella virus, the only member of the Rubivirus genus, causes rubella (also known as german measles),an acute exanthematous infection of children and adults. The clinical illness is characterized by rash, fever and lymphadenopathy and can resemble a mild case of measles. The virus also causes arthralgias and occasional encephalitis.

Infection is particularly disastrous if contracted during the first 4 months of pregnancy. If not immunologically protected, women infected during pregnancy run a high risk of embryo-foetal damage. Congenital rubella causes a wide range of severe defects in the foetus, including cataract, deafness, hepatosplenomegaly, psychomotor retardation, bone alterations, cardiopathies, neuropathies and diabetes.

Detection of Rubella specific IgM and IgG antibodies is an thus essential tool for diagnosis and follow up of acute infection, assessment of immune status in women of child-bearing age and determination of seroconversion after vaccination.

Rubella specific IgM reaches high levels in serum 2 weeks after the rash and lasts in the circulation for one to two month(s). Specific IgG generally appears a few days after the onset of rash, about 1 week after IgM develops. It rapidly increases to reach a plateau 6 to 10 weeks after the onset of symptoms and then progressively decreases to a level (15-200 IU/mL) lasting for the whole life. Reinfection, completely asymptomatic, is accompanied by moderately increased levels of specific IgG. A four-fold or greater increase in Rubella antibody titre, between acute (8 days after onset of rash) and convalescent sera taken 1-3 weeks apart, is considered diagnostic for acute Rubella infection. Hence paired testing is recommended.

IgG avidity testing is recommended to differentiate between primary infection and reactivation. A positive IgM accompanied by low-avidity IgG is suggestive of a primary infection, whereas a high-avidity IgG indicates either IgM persistence or reactivation. A low avidity index may also be seen in a proportion of infected persons for months. Hence it is advised to perform IgM testing initially to point to the need for IgG avidity to avoid misinterpretation of results.

Seropositivity to Rubella IgG antibodies in all age groups have been reported to be as high as 94% based on premarital serological testing. Hence, all results must be interpreted in the context of the total clinical history and supplementary findings of other investigative procedures.

Test method: Enzyme Immunoassay.

RECOMMENDATIONS:
SRL Ranbaxy Laboratories recommends submission of an early convalescent specimen approximately 1 week after the first (Acute) specimen, if the latter was drawn within 8 days after rash onset. Also submit a late convalescent specimen 2-3 weeks after the acute specimen, if clinically indicated. Please provide the SRL Ranbaxy accession number of the acute specimen with the convalescent specimen.


RUBELLA VIRUS ANTIBODIES

Rubella virus, the only member of the Rubivirus genus, causes rubella (also known as german measles),an acute exanthematous infection of children and adults. The clinical illness is characterized by rash, fever and lymphadenopathy and can resemble a mild case of measles. The virus also causes arthralgias and occasional encephalitis.

Infection is particularly disastrous if contracted during the first 4 months of pregnancy. If not immunologically protected, women infected during pregnancy run a high risk of embryo-foetal damage. Congenital rubella causes a wide range of severe defects in the foetus, including cataract, deafness, hepatosplenomegaly, psychomotor retardation, bone alterations, cardiopathies, neuropathies and diabetes.

Detection of Rubella specific IgM and IgG antibodies is an thus essential tool for diagnosis and follow up of acute infection, assessment of immune status in women of child-bearing age and determination of seroconversion after vaccination.

Rubella specific IgM reaches high levels in serum 2 weeks after the rash and lasts in the circulation for one to two month(s). Specific IgG generally appears a few days after the onset of rash, about 1 week after IgM develops. It rapidly increases to reach a plateau 6 to 10 weeks after the onset of symptoms and then progressively decreases to a level (15-200 IU/mL) lasting for the whole life. Reinfection, completely asymptomatic, is accompanied by moderately increased levels of specific IgG. A four-fold or greater increase in Rubella antibody titre, between acute (8 days after onset of rash) and convalescent sera taken 1-3 weeks apart, is considered diagnostic for acute Rubella infection. Hence paired testing is recommended.

IgG avidity testing is recommended to differentiate between primary infection and reactivation. A positive IgM accompanied by low-avidity IgG is suggestive of a primary infection, whereas a high-avidity IgG indicates either IgM persistence or reactivation. A low avidity index may also be seen in a proportion of infected persons for months. Hence it is advised to perform IgM testing initially to point to the need for IgG avidity to avoid misinterpretation of results.

Seropositivity to Rubella IgG antibodies in all age groups have been reported to be as high as 94% based on premarital serological testing. Hence, all results must be interpreted in the context of the total clinical history and supplementary findings of other investigative procedures.

Test method: Enzyme Immunoassay.

RECOMMENDATIONS:
SRL Ranbaxy Laboratories recommends submission of an early convalescent specimen approximately 1 week after the first (Acute) specimen, if the latter was drawn within 8 days after rash onset. Also submit a late convalescent specimen 2-3 weeks after the acute specimen, if clinically indicated. Please provide the SRL Ranbaxy accession number of the acute specimen with the convalescent specimen.


RUBELLA RNA PCR

Rubella virus, the only member of the Rubivirus genus, causes rubella, a mild rash which appears after an incubation period of 13-20 days. Rubella is infectious for ~7 days before and ~7-10 days after the exanthema; the virus causes arthralgias in ~50% of post-pubertal females as well as occasional encephalitis and, if the infection occurs during the first trimester of pregnancy, the congenital rubella syndrome(CRS).

Clinical Utility :
RT-PCR assays show the most promise for early, accurate prenatal diagnosis of rubella infection. RT-PCR can detect rubella in chorionic villus samples at 10 weeks and in amniotic fluid by 16 weeks and is also useful for prenatal diagnosis in the second trimester. RT-PCR can be used for patients with persistent specific IgM, often at low level. Reinfection in a patient with preexisting specific IgG above a defined cutoff can also be confirmed using RT-PCR test.

Interpretation:
Detection of specific amplification band of 143 bp indicates presence of Rubella RNA in the given sample. No target specific amplification indicates absence of Rubella RNA in the given sample. All the results should always be correlated with clinical status and history of the patient.

Limitations:
PCR is a highly sensitive technique; common reasons for paradoxical results are contamination during specimen collection, selection of inappropriate specimens and inherent PCR inhibitors in the specimen. Variation in results can be observed due to non-adherence to specimen collection protocol. Hence it recommended to immediately freeze EDTA plasma, CSF, Amniotic fluid or Nasal swab, after collection.

Test technique: Nested Reverse Transcriptase Polymerase Chain Reaction


SEMEN ANALYSIS, SEMEN

Test method: Physical, chemical and microscopy


SICKLE CELL PCR
Clinical utility:


Sickle Cell Disease is an autosomal recessive genetic disorder of the blood that results due to a single base-pair mutation, an A - T transversion in the sequence encoding codon 6 of the human Beta-globin.

Prevalence in
Maharashtra is less than 0.1% while it is very high (2 - 20 %) amongst the tribal population groups from Nandurbar and Gadchiroli districts of the State. The same tribal population groups residing in the neighboring states of Gujarat, Madhya Pradesh and Andhra Pradesh have a similar prevalence. The overall prevalence among tribal populations in India is about 10% for the carrier state and 0.5% for sufferers.

It can manifest in two forms viz. heterozygous (also called sickle cell trait or carrier) where only one of the two ß-globin genes is mutated and homozygous (sufferer or sickle cell disease) where both the ß-globin genes are mutated. When two carriers marry, the chance of having a homozygous child is 25% every pregnancy.

The test identifies the mutations in heterozygous or homozygous state.

Test method:
Polymerase Chain reaction

Interpretation:
Detection of A - T transversion mutation in heterozygous form confirms the carrier state or sickle cell trait.
Detection of - T transversion mutation in homozygous form confirms the sickle cell disease state in an individual.

Limitation:
PCR is a highly sensitive technique; common reasons for paradoxical results are contamination during specimen collection, selection of inappropriate specimens and inherent PCR inhibitors in the specimen.

"This test is developed and validated at SRL Ranbaxy Ltd. Due to limited population specific data, currently this test is meant for research use only".


SICKLE CELL PCR PND
Clinical utility:


Sickle Cell Disease is an autosomal recessive genetic disorder of the blood that results due to a single base-pair mutation, an A - T transversion in the sequence encoding codon 6 of the human Beta-globin.

Prevalence in
Maharashtra is less than 0.1% while it is very high (2 - 20 %) amongst the tribal population groups from Nandurbar and Gadchiroli districts of the State. The same tribal population groups residing in the neighboring states of Gujarat, Madhya Pradesh and Andhra Pradesh have a similar prevalence. The overall prevalence among tribal populations in India is about 10% for the carrier state and 0.5% for sufferers.

It can manifest in two forms viz. heterozygous (also called sickle cell trait or carrier) where only one of the two ß-globin genes is mutated and homozygous (sufferer or sickle cell disease) where both the ß-globin genes are mutated. When two carriers marry, the chance of having a homozygous child is 25% every pregnancy. Couples at risk for passing on Sickle Cell Disease should consider prenatal diagnosis to prevent sickle cell disease in children.

The test identifies the mutations in heterozygous or homozygous state. The test identifies these common mutations in parents and correlates the status of the same mutation in the fetus.

The VNTR analysis is done to rule out maternal cell contamination.

Test method:

VNTR analysis for maternal cell contamination and Polymerase Chain reaction for mutation detection

Interpretation:
Detection of A - T transversion mutation in heterozygous form confirms the carrier state or sickle cell trait.
Detection of - T transversion mutation in homozygous form confirms the sickle cell disease state in the fetus.
The test results should always be correlated with parental mutation analysis.

Limitation:
PCR is a highly sensitive technique; common reasons for paradoxical results are contamination during specimen collection, selection of inappropriate specimens and inherent PCR inhibitors in the specimen.

"This test is developed and validated at SRL Ranbaxy Ltd. Due to limited population specific data, currently this test is meant for research use only".


SICKLE CELL VARIANT ANALYSIS DRIED BLOOD SPOT
The presence of hemoglobin S (HbS) in the neonatal specimen collected on filter paper is indicative of sickle cell disease or sickle cell trait.

The Sickle Cell Short program utilizes the principles of cation-exchange high performance liquid chromatography (HPLC). It is a fast and accurate method for determining the presence and quantity of various Hb. This method is designed to resolve hemoglobins (Hb) F, A, S, D, C, and E.

The frequently occurring Neonatal phenotypes are as follows:
• Hb FA – Normal Hemoglobin pattern – Healthy Neonate
• HB FS – Sickle Cell Anemia-Chronic hemolytic anemia
• Hb FAS – Sickle Cell Trait – Possible mild anemia
• Hb FC – Hemoglobin C Disease – Mild hemolytic anemia
• Hb FC – Hemoglobin C Trait – Possible mild anemia
• Hb FD – Hemoglobin D Disease – Mild hemolytic anemia
• Hb FAD – Hemoglobin D Trait – Possible mild anemia
• Hb FE – Hemoglobin E Disease – Mild hemolytic anemia
• Hb FAE – Hemoglobin E Trait – Possible mild anemia
• Hb FSC – Hemoglobin SC Disease – Chronic hemolytic anemia

If the test shows the presence of sickle hemoglobin, a second blood test is performed to confirm the diagnosis. Sample stability is upto 48hours at 2-4 degrees celsius.

Test method: High Performance Liquid Chromatography (HPLC)

References :
1. Frempong T,.Pearson HA. Newborn screening coupled with comprehensive follow-up reduced early mortality of sickle cell disease in
Connecticut. Connecticut Medicine.71(1):9-12, 2007.
2. Biagioli FE, DeVoe JE, Hamilton A, WinklerPrins V. Clinical inquiries. What are appropriate screening tests for infants and children. [Review] [7 refs]. Journal of Family Practice 55(9):803-8, 2006.
3. Boemer F, Vanbellinghen J-F, Bours V, Schoos R. Screening for sickle cell disease on dried blood: A new approach evaluated on 27,000 Belgian newborns. Journal of Medical Screening.Vol.13(3)(pp 132-136), 2006

SICKLING TEST, BLOOD

Red blood cells containing Hemoglobin S assume a sickle shape when incubated with a freshly prepared solution of the reducing agent sodium meta-bisulphite. This serves as a screening test for sickle cell disease.

Test method: Deoxygenation, Microscopy


SKIN TEST - MANTOUX

Positive reaction: Induration and erythema of 10 mm or above
Negative reaction: Induration and erythema of less than 4 mm
Borderline reaction: Induration and erythema of 5 mm to 9mm

Limitations of the test
1. The conditions like measles, mumps, polio may hinder the activity of tuberculin.
2. The positive reaction should be judged after careful history of age, habitat, place of work of the individual. However a positive reaction does not always indicate active disease. Further investigations like culture, microscopy etc should be carried out before drawing the final conclusion.


SODIUM, SERUM

Test method: ISE (Ion selective electrode)


SODIUM, URINE


Test method: ISE (Ion selective electrode)


SPERM ANTIBODIES

Antisperm antibodies are recognized as a significant factor in the etiology of immunologically related subfertility. Men as well women are capable of producing antibodies against human spermatozoa. Spermatozoa are separated from the immune system in men by the so-called blood testicular barrier. When the barrier breaks down, e.g. in testicular trauma, vasectomy, obstruction of the epididymis duct or in infection they act as immunogens. In women it has been postulated that non-specific bacterial or viral infections can lead to the induction of antibodies cross- reactive with spermatozoan antigens.

The only antibodies of clinical significance are those which are specific for the sperm plasma membrane. They process the ability to affect the motility properties of the sperm cells or their participation in the infertility processes including acrosome reaction and capacitation.

Test method: Enzyme Immuno-Assay.


STOOL FOR OCCULT BLOOD

Fecal occult blood is a term used to determine the presence of blood in the feces. Blood is present in the feces due to bleeding from the gastrointestinal tract. Small increases in blood content may not alter the appearance of the stool and such stools are said to contain "occult blood", detection of which can be most useful in uncovering and localizing disease. Screening for occult blood is especially important because over one half of all cancers (excluding skin) are those of the gastrointestinal tract. Early diagnosis and treatment of patients with colonic cancer results in a relative good prognosis for survival. Fecal occult blood tests are recommended for use as an aid to routine physical examinations, routine hospital testing, and screening for gastro-intestinal bleeding from any source including colorectal cancer. The occult blood may be falsely positive in case of ingestion of raw meat, red broccoli, vitamin C, NSAIDs etc or exogenous bleeding like hemorrhoids and menstruation. A repeat test is suggested after avoiding the above for at least 2 days, if clinically indicated.


SYPHILIS ANTIBODIES, SERUM

Syphilis is a disease caused by infection with the spirochete bacterium Treponema pallidum, ordinarily transmitted by sexual contact. However, it can also be transmitted congenitally by transplacental passage of Treponema pallidum to the foetus and by blood transfusion. The serological diagnosis of syphilis is performed demonstrating the presence of significant levels of specific Treponema pallidum antibodies in the serum sample.

A positive result indicates a current or past infection with T. pallidum. The clinical history of the patient must be taken in consideration. A negative result does not exclude the possibility of exposure or infection with T. pallidum.

Test method: Enzyme Immunoassay.


TREPONEMA PALLIDUM HEMAGGLUTINATION

A Positive reaction indicates the presence of antibodies to T. Pallidum, resulting from past or present infection. An Intermediate result may correspond to low levels of antibodies in early stages of Syphilis or to residual antibodies in treated Syphilis. In this case, a further sample should be tested to demonstrate a possible rise in antibody titre. The TPHA technique may give cross reactions with other forms of Treponemal infection and false Positive reaction in a small percentage of samples from patients with Infectious Mononucleosis, Leprosy, Autoimmune disease and drug addiction. Occasionally in early primary syphilis, the specific antibodies may not be detected by TPHA technique.

******* Please Note : The significant titre for this test is 1:80 and above.

Test Method : Plate Hemagglutination.

Testing was performed at ACM Medical Laboratory, 160 Elmgrove Park,Rochester, NY 14624, +1-585-429-2374
This test is not covered under the scope of accreditation of NABL and CAP of SRL.


Testing was performed at ACM Medical Laboratory, 160 Elmgrove Park,
Rochester, NY 14624, +1-585-429-2374
This test is not covered under the scope of accreditation of NABL and CAP of SRL.


TESTOSTERONE, TOTAL, SERUM

Testosterone is the major androgen in males and is produced by the Leydig cells of the testes. Testosterone circulates primarily as a protein bound steroid and strongly binds to plasma proteins such as sex hormone binding globulin (SHBG) or testosterone-estradiol-binding globulin (TeBG). Testosterone also binds with low affinity to cortisol binding globulin (CBG) and albumin. Less than 2.5% of testosterone circulates unbound to plasma proteins.

In adult males, testosterone levels show a diurnal variation with the highest levels detected in the early morning and the lowest level in the evening. Levels also increase after exercise and gradually decrease with advancing age. In adult females, testosterone levels are much lower than adult males (usually 5-10% that of males levels). The major sources of testosterone in females are the ovaries, the adrenal glands and the peripheral conversion of precursors, specifically androstenedione to testosterone.

Clinical entities in which testosterone is increased include gonadal & adrenal tumors, adrenal hyperplasia and polycystic ovaries (Stein-Leventhal syndrome). The clinical manifestations of excess testosterone include infertility, hirsutism, ammenorhea and obesity. Decreased levels of testosterone are associated with conditions such as hypogonadism, hypopitutarism, orchiectomy, estrogen therapy, testicular failure, hyperprolactinemia, some cases of Klinefelter's syndrome, some types of liver and kidney diseases and critical illness. Clinical applications of serum testosterone tests in pediatrics include detection precocious puberty, hypogonadism in adolescent boys, pituitary or hypothalamic disease, where both testosterone and gonadotropin concentrations are low and virilization in girls.

Heterophilic antibodies in human serum can react with reagent immunogobulins, interfering with in-vitro immunoassays. Patients routinely exposed to animals or animal serum products can be prone to this interference and anomalous values may be observed. "In range" and "Out of range" flagging is applicable for testosterone assay, only if age of the patient is mentioned.

Test method: Chemiluminescence


TESTOSTERONE,FREE/TOTAL, SERUM
Testosterone is the major androgen in males and is produced by the Leydig cells of the testes. Testosterone circulates primarily as a protein bound steroid and strongly binds to plasma proteins such as sex hormone binding globulin (SHBG) or testosterone-estradiol-binding globulin (TeBG). Testosterone also binds with low affinity to cortisol binding globulin (CBG) and albumin. Less than 2.5% of testosterone circulates unbound to plasma proteins.
In adult males, testosterone levels show a diurnal variation with the highest levels detected in the early morning and the lowest level in the evening. Levels also increase after exercise and gradually decrease with advancing age.
In adult females, testosterone levels are much lower than adult males (usually 5-10% that of males levels). The major sources of testosterone in females are the ovaries, the adrenal glands and the peripheral conversion of precursors, specifically androstenedione to testosterone.
Clinical entities in which testosterone is increased include gonadal & adrenal tumors, adrenal hyperplasia and polycystic ovaries (Stein-Leventhal syndrome). The clinical manifestations of excess testosterone include infertility, hirsutism, ammenorhea and obesity.
Decreased levels of testosterone are associated with conditions such as hypogonadism, hypopitutarism, orchiectomy, estrogen therapy, testicular failure, hyperprolactinemia, some cases of Klinefelter's syndrome, some types of liver and kidney diseases and critical illness.
Clinical applications of serum testosterone tests in pediatrics include detection precocious puberty, hypogonadism in adolescent boys, pituitary or hypothalamic disease, where both testosterone and gonadotropin concentrations are low and virilization in girls.
Heterophilic antibodies in human serum can react with reagent immunogobulins, interfering with in-vitro immunoassays. Patients routinely exposed to animals or animal serum products can be prone to this interference and anomalous values may be observed.
Hormone assay values are to be correlated with the age and clinical status of the patient irrespective of whether the values are appearing in the 'In Range' or 'Out of Range' columns.

TESTOSTERONE, FREE
Most circulating Testosterone is bound to a specific carrier protein usually called Sex Hormone - Binding Globulin (SHBG) or Testosterone Binding Globulin (TeBG). A small portion of testosterone exists in the free & unbound state available for entry into the cells of target organs. Free Testosterone is probably the physiologically active component of testosterone.
The serum Free Testosterone assay was developed because the measurement of total Testosterone does not always give an accurate picture of the amount of testosterone available to target organ cells. Free Testosterone estimation is useful for suspected increases in physiologically active testosterone. An apparent inverse correlation of free Testosterone with age is noted in adult males.

The below mentioned are the guidelines for age related
Referance Ranges of Free Testosterone.

TESTOSTERONE FREE:
MALE (20-39 YRS): 8.8 - 27.0 pg/mL
MALE (40-59 YRS): 7.2 - 23.0 pg/mL
MALE (60-80 YRS): 5.6 - 19.0 pg/mL
FEMALES:
FEMALES (20-39 YRS): 0.06 - 2.57 pg/mL
FEMALES (40-59 YRS): 0.04 - 2.03 pg/mL
FEMALES (60-80 YRS): 0.03 - 1.55 pg/mL

Test method: Testosterone by Chemiluminescence and Free Testosterone by Radio Immunoassay.

The clone for “THYROGLOBULIN" antibody is “1D4”.


THYROGLOBULIN, SERUM

Thyroglobulin is a glycoprotein synthesized by the thyroid gland. The major clinical applications of thyroglobulin derive form the fact that a functioning thyroid tissue appears to be the only source of circulating thyroglobulin.

The major utility of thyroglobulin estimation is to assess the presence and possibly the extent of residual, recurrent or metastatic follicular or papillary thyroid carcinoma after therapy. In patients with these carcinomas treated with total thyroidectomy, or radio-active iodine and taking thyroid hormonal therapy, thyroglobulin is undetectable if functional tumor is absent, but detected if functional tumor is present. Thyroglobulin correlates with the tumor mass, with highest values in patients with metastases to bones & lungs.

Thyroglobulin estimation is not recommended for the initial diagnosis of thyroid carcinoma. This assay should not be used in pre-existing thyroid disorders. Thyroglobulin is also used to predict outcome of therapy for hyperthyroidism; higher remission rates in patients with lower thyroglobulin values. Failure to become normal after drug-induced remission suggests relapse after drugs are discontinued.

Thyroglobulin levels are increased in most patients with differentiated thyroid carcinoma but not those with undifferentiated or medullary thyroid carcinoma. Levels may also be elevated in hyperthyroidism, sub-acute thyroiditis, non-toxic nodular goiter & marked liver insufficiency.

Decreased levels are observed in thyroid agenesis in newborns.

Heterophilic antibodies in human serum can react with the immunoglobulins included in the assay components causing interference with the assay.

Thyroglobulin antibodies can interfere with this immunoassay.

Test method: Chemiluminescence.


THYROID PANEL BY CHEMILUMINESCENCE, SERUM

Primary malfunction of the thyroid gland may result in excessive (hyper) or below normal (hypo) release of T3 or T4. In addition, as TSH directly affects thyroid function, malfunction of the pituitary or the hypothalamus influences the thyroid gland activity. Disease in any portion of the thyroid-pituitary-hypothalamus system may influence the levels of T3 and T4 in the blood. In primary hypothyroidism, TSH levels are significantly elevated, while in secondary and tertiary hypothyroidism, TSH levels may be low. In addition, in the Euthyroid Sick Syndrome, multiple alterations in serum thyroid function test findings have been recognized in patients with a wide variety of nonthyroidal illness (NTI) without evidence of preexisting thyroid or hypothalamic-pituitary disease.
Thyroid Binding Globulin (TBG) concentrations remain relatively constant in healthy individuals. However, pregnancy, excess estrogens, androgens, anabolic steroids and glucocorticoids are known to alter TBG levels and may cause false thyroid values for Total T3 and T4 tests.

Below mentioned are the guidlines for Pregnancy related reference ranges for Total T4, TSH & Total T3
---------------------------------------------------------------------------------------------------------
Levels in TOTAL T4 TSH TOTAL T3
Pregnancy (µg/dL) (µIU/mL) (ng/dL)

First Trimester 6.6 - 12.4 0.3 - 4.5 81 - 190
.
2nd Trimester 6.6 - 15.5 0.5 - 4.6 100 - 260
.
3rd Trimester 6.6 - 15.5 0.8 - 5.2 100 - 260
-------------------------------------------------------------------------------------------------------

Below mentioned are the guidelines for age related reference ranges for T3, T4 and TSH result
. T3 T4 TSH
. (ng/dL) (µg/dL) (µIU/mL)
Cord Blood: 30 - 70 1-3 day: 8.2 - 19.9 Birth-4 Day: 1.0 - 38.9
New Born: 75 - 260 1 Week: 6.0 - 15.9 2 - 20 Weeks: 1.7 - 9.1
1-5 Years: 100 - 260 1-12 Months: 6.1 - 14.9 20 Weeks-20 Years: 0.7 -6.4
5 - 10 Years: 90 - 240 1 - 3 Years: 6.8 - 13.5
10 - 15 Years: 80 - 210 3 - 10 Years: 5.5 - 12.8

Reference:
1. Burtis C.A., Ashwood E. R. Bruns D.E. Teitz textbook of Clinical Chemistry and Molecular Diagnostics, 4th Edition.
2. Gowenlock A.H. Varley's Practical Clinical Biochemistry, 6th Edition.
3. Behrman R.E. Kilegman R.M., Jenson H. B. Nelson Text Book of Pediatrics, 17th Edition

Test method: Chemiluminescence


THYROID PANEL BY CHEMILUMINESCENCE, SERUM

Primary malfunction of the thyroid gland may result in excessive (hyper) or below normal (hypo) release of T3 or T4. In addition, as TSH directly affects thyroid function, malfunction of the pituitary or the hypothalamus influences the thyroid gland activity. Disease in any portion of the thyroid-pituitary-hypothalamus system may influence the levels of T3 and T4 in the blood. In primary hypothyroidism, TSH levels are significantly elevated, while in secondary and tertiary hypothyroidism, TSH levels may be low. In addition, in the Euthyroid Sick Syndrome, multiple alterations in serum thyroid function test findings have been recognized in patients with a wide variety of nonthyroidal illness (NTI) without evidence of preexisting thyroid or hypothalamic-pituitary disease.
Thyroid Binding Globulin (TBG) concentrations remain relatively constant in healthy individuals. However, pregnancy, excess estrogens, androgens, anabolic steroids and glucocorticoids are known to alter TBG levels and may cause false thyroid values for Total T3 and T4 tests.

Below mentioned are the guidlines for Pregnancy related reference ranges for Total T4, TSH & Total T3
---------------------------------------------------------------------------------------------------------
Levels in TOTAL T4 TSH TOTAL T3
Pregnancy (µg/dL) (µIU/mL) (ng/dL)

First Trimester 7.33 – 14.8 0.33 - 4.59 105 - 230
.
2nd Trimester 7.93 - 16.1 0.35 - 4.10 129 - 262
.
3rd Trimester 6.95 - 15.7 0.21 – 3.15 135 - 262
-------------------------------------------------------------------------------------------------------

Below mentioned are the guidelines for age related reference ranges for T3, T4 and TSH result
. T3 T4 TSH
. (ng/dL) (µg/dL) (µIU/mL)
0-6 days: 73-288 0-6 days: 5.04-18.5 0-6 days: 0.7-15.2
6days-3months: 80-275 6days-3months: 5.41-17.0 6days-3months: 0.72-11.0
3-12months: 86-265 3-12months: 5.67-16.0 3-12months: 0.73-8.35
1-6years: 92-248 1-6years: 5.95-14.7 1-6years: 0.7-5.97
6-11years: 93-231 6-11years: 5.99-13.8 6-11years: 0.6-4.84
11-20years: 91-218 11-20years: 5.91-13.2 11-20years: 0.51-4.30

Reference:
1. Burtis C.A., Ashwood E. R. Bruns D.E. Teitz textbook of Clinical Chemistry and Molecular Diagnostics, 4th Edition.
2. Gowenlock A.H. Varley's Practical Clinical Biochemistry, 6th Edition.
3. Behrman R.E. Kilegman R.M., Jenson H. B. Nelson Text Book of Pediatrics, 17th Edition

Test method: Chemiluminescence


THYROID PANEL BY CHEMILUMINESCENCE, SERUM

Primary malfunction of the thyroid gland may result in excessive (hyper) or below normal (hypo) release of T3 or T4. In addition, as TSH directly affects thyroid function, malfunction of the pituitary or the hypothalamus influences the thyroid gland activity. Disease in any portion of the thyroid-pituitary-hypothalamus system may influence the levels of T3 and T4 in the blood. In primary hypothyroidism, TSH levels are significantly elevated, while in secondary and tertiary hypothyroidism, TSH levels may be low. In addition, in the Euthyroid Sick Syndrome, multiple alterations in serum thyroid function test findings have been recognized in patients with a wide variety of nonthyroidal illness (NTI) without evidence of preexisting thyroid or hypothalamic-pituitary disease.
Thyroid Binding Globulin (TBG) concentrations remain relatively constant in healthy individuals. However, pregnancy, excess estrogens, androgens, anabolic steroids and glucocorticoids are known to alter TBG levels and may cause false thyroid values for Total T3 and T4 tests.

Below mentioned are the guidlines for Pregnancy related reference ranges for Total T4, TSH & Total T3
---------------------------------------------------------------------------------------------------------
Levels in TOTAL T4 TSH TOTAL T3
Pregnancy (µg/dL) (µIU/mL) (ng/dL)

First Trimester 6.6 - 12.4 0.3 - 4.5 81 - 190
.
2nd Trimester 6.6 - 15.5 0.5 - 4.6 100 - 260
.
3rd Trimester 6.6 - 15.5 0.8 - 5.2 100 - 260
-------------------------------------------------------------------------------------------------------

Below mentioned are the guidelines for age related reference ranges for T3, T4 and TSH result
. T3 T4 TSH
. (ng/dL) (µg/dL) (µIU/mL)
Cord Blood: 30 - 70 1-3 day: 8.2 - 19.9 Birth-4 Day: 1.0 - 38.9
New Born: 75 - 260 1 Week: 6.0 - 15.9 2 - 20 Weeks: 1.7 - 9.1
1-5 Years: 100 - 260 1-12 Months: 6.1 - 14.9 20 Weeks-20 Years: 0.7 -6.4
5 - 10 Years: 90 - 240 1 - 3 Years: 6.8 - 13.5
10 - 15 Years: 80 - 210 3 - 10 Years: 5.5 - 12.8

Reference:
1. Burtis C.A., Ashwood E. R. Bruns D.E. Teitz textbook of Clinical Chemistry and Molecular Diagnostics, 4th Edition.
2. Gowenlock A.H. Varley's Practical Clinical Biochemistry, 6th Edition.

Test method: Chemiluminescence


THYROID STIMULATING HORMONE, SERUM


Thyroid-stimulating hormone is a glycoprotein with two non-covalently bound subunits. The alpha subunit is similar to those of follicle-stimulating hormone (FSH), human chorionic gonadotrophin (hCG) and Luteinizing hormone (LH). The beta subunit of TSH is unique, which results in the specific biochemical and immunological properties of this hormone.

TSH is synthesized and secreted by the anterior pituitary in response to a negative feedback mechanism involving concentrations of FT3 (Free T3) and FT4 (Free T4). Additionally, the hypothalamic tripeptide, thyrotropin-releasing hormone (TRH), directly stimulates TSH production.

TSH interacts with specific cell receptors on the thyroid cell surface and exerts two main actions. The first action is to stimulate cell reproduction and hypertrophy. Secondly, TSH stimulates the thyroid gland to synthesize and secrete T3 and T4.

The ability of quantitate circulating levels of TSH is important in evaluating thyroid function. It is especially useful in the differential diagnosis of primary (thyroid) from secondary (pituitary) and tertiary (hypothalamic) hypothyroidism. In primary hypothyroidism, TSH levels are significantly elevated, while in secondary and tertiary hypothyroidism, TSH levels are low.

TRH stimulation differentiates secondary and tertiary hypothyroidism by observing the change in patient TSH levels. Typically, the TSH response to TRH stimulation is absent in cases of secondary hypothyroidism and normal to exaggerated in tertiary hypothyroidism.

Historically, TRH stimulation has been used to confirm primary hyperthyroidism, indicated by elevated T3 and T4 levels and low or undetectable TSH levels. TSH assays with increased sensitivity and specificity provide a primary diagnostic tool to differentiate hyperthyroid from euthyroid patients.

Below mentioned are the guidelines for age related reference ranges of TSH:
Age Reference Range Units

Cord Blood 2.0 - 40.0 µIU/ml

1 - 6 days 0.4 - 15.0 µIU/ml

1 - 3 weeks 0.4 - 10.0 µIU/ml

1 month & over 0.4 - 5.5 µIU/ml


THYROID STIMULATING HORMONE

Thyroid Stimulating Hormone (TSH) is a glycoprotein produced from anterior lobe of the pituitary gland. TSH is carried by the blood stream to the thyroid gland where it stimulates the synthesis and secretion of the thyroid hormones. Serum levels of TSH are regulated through a feedback control system involving the hypothalamus, pituitary, and thyroid glands. When thyroid hormone levels are increased as in hyperthyroidism, TSH secretion is inhibited. Conversely, when thyroid levels are decreased as in hypothyroidism, TSH secretion is stimulated. Congenital Hypothyroidism (CH) occurs in approximately 1:4000 newborns. CH can result in mental retardation that is easily prevented by early treatment.

This test is intended as a screening method for measuring the TSH concentrations in newborn blood spot specimens for Congenital Hypothyroidism. TSH values below 10 mIU/ml are considered as normal. Values greater than 20 mIU/ml are considered as presumptive positive, while values between 10-20 mIU/ml are considered as borderline.

Limitation:
1) Results from specimens collected less than 48 hours after birth should be treated with caution due to the increased risk of false positive results. Additionally, specimens from premature infants and newborns who have received blood transfusions may not provide an accurate assessment of the thyroid status of the newborn.

2) When TSH is used as the primary screening test, newborns with TBG deficiency (frequency: 1:5,000 to 1:10,000), hypothalamic-pituitary hypothyroidism (frequency: 1:5,000) and hypothyroxinemia with delayed TSH elevation may be missed.

3) Patient diagnosis should not be made solely on the basis of an elevated blood spot TSH concentration. Elevated TSH concentrations are not diagnostic per se of thyroid disease but indicate the need for further study of the newborn from which the 'presumptive positive' specimen was obtained.

Test Technique: Enzyme Immuno-Assay


THYROID STIMULATING HORMONE, SERUM
Thyroid-stimulating hormone is a glycoprotein with two non-covalently bound subunits. TSH is synthesized and secreted by the anterior pituitary in response to a negative feedback mechanism involving concentrations of FT3 (Free T3) and FT4 (Free T4). Additionally, the hypothalamic tripeptide, thyrotropin-releasing hormone (TRH), directly stimulates TSH production. TSH interacts with specific cell receptors on the thyroid cell surface and exerts two main actions. The first action is to stimulate cell reproduction and hypertrophy. Secondly, TSH stimulates the thyroid gland to synthesize and secrete T3 and T4. The ability of quantitate circulating levels of TSH is important in evaluating thyroid function. It is especially useful in the differential diagnosis of primary (thyroid) from secondary (pituitary) and tertiary (hypothalamic) hypothyroidism. In primary hypothyroidism, TSH levels are significantly elevated, while in secondary and tertiary hypothyroidism, TSH levels are low. TRH stimulation differentiates secondary and tertiary hypothyroidism by observing the change in patient TSH levels. Typically, the TSH response to TRH stimulation is absent in cases of secondary hypothyroidism and normal to exaggerated in tertiary hypothyroidism. TSH assays with increased sensitivity and specificity provide a primary diagnostic tool to differentiate hyperthyroid from euthyroid patients.

Below mentioned are the guidelines for Pregnancy related reference ranges for TSH
---------------------------------------------------------------------------------------------------------
Levels in TSH
Pregnancy (µIU/mL)
First Trimester 0.33 - 4.59
2nd Trimester 0.35 - 4.10
3rd Trimester 0.21 – 3.15
-------------------------------------------------------------------------------------------------------
Below mentioned are the guidelines for age related reference ranges of TSH:
Age Reference Range Units
0-6 days 0.7 – 15.2 µIU/mL
6days – 3months 0.72 – 11.0 µIU/mL
3-12 months 0.73 – 8.35 µIU/mL
1-6 years 0.7 – 5.97 µIU/mL
6-11 years 0.6 – 4.84 µIU/mL
11-20 years 0.51 – 4.30 µIU/mL

Reference:
1. Burtis C.A., Ashwood E. R. Bruns D.E. Teitz textbook of Clinical Chemistry and Molecular Diagnostics, 4th Edition.
2. Gowenlock A.H. Varley's Practical Clinical Biochemistry, 6th Edition.
3. Behrman R.E. Kilegman R.M., Jenson H. B. Nelson Text Book of Pediatrics, 17th Edition

Test method: CHEMILUMINESCENCE


THYROID STIMULATING HORMONE, SERUM

Thyroid-stimulating hormone is a glycoprotein with two non-covalently bound subunits. TSH is synthesized and secreted by the anterior pituitary in response to a negative feedback mechanism involving concentrations of FT3 (Free T3) and FT4 (Free T4). Additionally, the hypothalamic tripeptide, thyrotropin-releasing hormone (TRH), directly stimulates TSH production. TSH interacts with specific cell receptors on the thyroid cell surface and exerts two main actions. The first action is to stimulate cell reproduction and hypertrophy. Secondly, TSH stimulates the thyroid gland to synthesize and secrete T3 and T4. The ability of quantitate circulating levels of TSH is important in evaluating thyroid function. It is especially useful in the differential diagnosis of primary (thyroid) from secondary (pituitary) and tertiary (hypothalamic) hypothyroidism. In primary hypothyroidism, TSH levels are significantly elevated, while in secondary and tertiary hypothyroidism, TSH levels are low. TRH stimulation differentiates secondary and tertiary hypothyroidism by observing the change in patient TSH levels. Typically, the TSH response to TRH stimulation is absent in cases of secondary hypothyroidism and normal to exaggerated in tertiary hypothyroidism. TSH assays with increased sensitivity and specificity provide a primary diagnostic tool to differentiate hyperthyroid from euthyroid patients.

Below mentioned are the guidelines for Pregnancy related reference ranges for TSH
---------------------------------------------------------------------------------------------------------
Levels in TSH
Pregnancy (µIU/mL)
First Trimester 0.3 - 4.5
2nd Trimester 0.5 - 4.6
3rd Trimester 0.8 - 5.2
-------------------------------------------------------------------------------------------------------
Below mentioned are the guidelines for age related reference ranges of TSH:
Age Reference Range Units
Birth - 4 days 1.0 - 38.9 µIU/mL
2 - 20 Weeks 1.7 - 9.1 µIU/mL
20 weeks - 20 years 0.7 - 6.4 µIU/mL

Reference:
1. Burtis C.A., Ashwood E. R. Bruns D.E. Teitz textbook of Clinical Chemistry and Molecular Diagnostics, 4th Edition.
2. Gowenlock A.H. Varley's Practical Clinical Biochemistry, 6th Edition.
3. Behrman R.E. Kilegman R.M., Jenson H. B. Nelson Text Book of Pediatrics, 17th Edition

Test method: CHEMILUMINESCENCE

TORCH IgG & IgM EVALUATION, SERUM

This panel consists of detection of IgM and IgG antibodies formed against Toxoplasma gondii, Rubella Virus, Cyto-Megalo Virus and Herpes Simplex Virus infections. These infections are generally asymptomatic, benign or self-limiting. However, in pregnant women these infections may result in recurrent fetal loss or as in Congenital Toxoplasmosis infection may result in prematurity to generalized or neurological symptoms.

Increased levels:
Increased levels of IgM antibodies generally indicate acute or recent infection. Increased levels of IgG antibodies may indicate old or chronic infection or previously immunized individual.

Decreased levels:
Decreased levels of IgG or IgM antibodies may be associated with immuno- compromised state. Decreased IgG levels may indicate absence of exposure to infection or absence of immunization. Absence of infection/ reactivation of infection may have to be confirmed/ ruled out by testing of paired sera for significant/ low level of positivity in sample collected during convalescent phase. In case, clinical evaluation & low antibody levels of TORCH group of organisms indicate absence of infection/ vaccination, immunization against organisms having vaccine may have to be considered to protect the patient.

RECOMMENDATIONS:
Paired testing of acute and convalescent phase sera is recommended, if clinically indicated. Please provide the SRL Ranbaxy Laboratories accession number of the specimen when submitting follow-up sera.
The sera will be tested simultaneously to optimize the utility of the results. All sera are stored frozen for six weeks for additional testing.
SRL Ranbaxy strongly recommends simultaneous testing of maternal and infant sera, if clinically indicated for suspected CNS Toxoplasmosis.


TORCH IgG EVALUATION, SERUM

This panel consists of detection of IgG antibodies formed against Toxoplasma gondii, Rubella Virus, Cyto-Megalo Virus and Herpes Simplex Virus infections. These infections are generally asymptomatic, benign or self-limiting. However, in pregnant women these infections may result in recurrent fetal loss or as in Congenital Toxoplasmosis infection may result in prematurity to generalized or neurological symptoms.

Increased levels:
Increased levels of IgG antibodies may indicate old or chronic infection or previously immunized individual.

Decreased levels:
Decreased levels of IgG or IgM antibodies may be associated with immuno- compromised state. Decreased IgG levels may indicate absence of exposure to infection or absence of immunization. Absence of infection/ reactivation of infection may have to be confirmed/ ruled out by testing of paired sera for significant/ low level of positivity in sample collected during convalescent phase. In case, clinical evaluation & low antibody levels of TORCH group of organisms indicate absence of infection/ vaccination, immunization against organisms having vaccine may have to be considered to protect the patient.

RECOMMENDATIONS:
Paired testing of acute and convalescent phase sera is recommended, if clinically indicated. Please provide the SRL Ranbaxy Laboratories accession number of the specimen when submitting follow-up sera.
The sera will be tested simultaneously to optimize the utility of the results. All sera are stored frozen for six weeks for additional testing.
SRL Ranbaxy strongly recommends simultaneous testing of maternal and infant sera, if clinically indicated for suspected CNS Toxoplasmosis.

Test method: Enzyme Immuno-Assay


TORCH IgM EVALUATION, SERUM

This panel consists of detection of IgM antibodies formed against Toxoplasma gondii, Rubella Virus, Cyto-Megalo Virus and Herpes Simplex Virus infections. These infections are generally asymptomatic, benign or self-limiting. However, in pregnant women these infections may result in recurrent fetal loss or as in Congenital Toxoplasmosis infection may result in prematurity to generalized or neurological symptoms.

Increased levels:
Increased levels of IgM antibodies generally indicate acute or recent infection. In Toxoplasma infection detection of IgG & IgM antibodies, approximate time of infection can be determined, by comparing rise or fall in anti body levels in paired sera. In CMV positive reports indicate primary or reactivated infection. Significantly high proportion of AIDS patients are sero- positive for CMV antibodies prior to detection of HIV infection. CMV antibody positive patients with HIV infection, progress to CNS or Peripheral Nervous system manifestations including Encephalitis.

Decreased levels:
Decreased levels of IgM antibodies may be associated with immuno- compromised state. Reactivation of infection may have to be confirmed/ruled out by testing of paired sera for sero- conversion.

RECOMMENDATIONS:
Paired testing of acute and convalescent phase sera is recommended, if clinically indicated. Please provide the SRL Ranbaxy Laboratories accession number of the specimen when submitting follow-up sera.
The sera will be tested simultaneously to optimize the utility of the results. All sera are stored frozen for six weeks for additional testing.
SRL Ranbaxy strongly recommends simultaneous testing of maternal and infant sera, if clinically indicated for suspected CNS Toxoplasmosis.

Test method: Enzyme Immuno-Assay.

TOTAL BILE ACIDS

Bile acids are synthesised in the liver as a breakdown product of cholesterol and secreted into the gall bladder. They are released into the small intestine where they solubilise dietary lipids such as cholesterol, aiding their absorption into the bloodstream. Bile acids are reabsorbed from the portal blood by hepatocyte extraction and re-excreted into bile for reuse. They pass through the enterohepatic circulation several times before final excretion. A proportion escapes into the circulation and can be measured in serum. The efficiency of bile acids extraction from the blood declines with decreasing liver function, causing the serum bile acids level to rise. The measurement of bile acids is a sensitive indicator of liver function. Bile acids levels also rise when bile flow is reduced or blocked (cholestasis) and additional bile acids escape into the bloodstream.

Clinical utility:
Liver disease symptoms are variable and non-specific. Common symptoms include jaundice, weight loss and behavioural changes but symptoms may not occur until there is substantial liver damage. Total bile acids testing can be used in the diagnosis and prognosis of liver disease. Levels rise in many liver diseases, for example hepatitis and biliary sclerosis. Abnormal levels in fasting patients or immediately after a meal can be used to detect liver disease and damage, impaired liver function, intestinal dysfunction and gall bladder blockage. Total bile acids testing may detect some forms of liver disease earlier than standard liver tests because bile acids levels correspond to liver function rather than liver damage. Total bile acids testing is the most sensitive test for obstetric cholestasis in pregnancy, where the flow through the bile ducts is reduced. It has also been used for diagnosis of hepatocellular carcinoma.

Test technique: Biochemistry

BIOCHEMISTRY TEST PERFORMED ON DADE BEHRING INSTRUMENT


TOTAL IRON BINDING CAPACITY, SERUM


TIBC is a useful diagnostic test in etio-morphological classification of anemia. TIBC is recommended to be performed in case serum iron is measured to calculate percent saturation of iron deficiency.

Test Technique: Colorimetric


TOTAL IgE, SERUM

Immunoglobulin E (IgE) is a trace protein in serum, and normally accounts for less than 0.001% of total serum immunoglobulins. The concentration of IgE in serum is age dependent and normally remains at levels less than 10 IU/mL in most infants during the first year of life. The level of serum IgE rises during childhood and reaches adult levels during the teens. There is a wide distribution of expected serum IgE values in healthy individuals of the same age group.

Because IgE is a mediator of the allergic response, quantitative measurement of serum IgE, when integrated with other clinical indicators, can provide useful information for the differential clinical diagnosis of atopic and non-atopic disease. Patients with atopic disease, including allergic asthma, allergic rhinitis, and atopic dermatitis commonly have moderately elevated serum IgE levels. However, a serum IgE level that is within the range of normally expected values does not rule out a limited set of IgE-dependent allergies.

Total serum IgE measurements may be most valuable for children to assist in differentiating between atopic and non-atopic individuals and to predict the probability of developing allergic disorders. Elevated serum IgE in neonates and children under two years of age is often associated with the development of a clinically significant atopic allergic disorder. There is not, however, a close correlation between the severity of the allergic reaction and the concentration of IgE antibodies in serum.

Total serum IgE levels may also be elevated in the presence of some clinical conditions that are not related to allergy. These clinical conditions include parasitic infections, immunodeficiency states, autoimmune diseases, Hodgkin's disease, bronchopulmonary aspergillosis, IgE myeloma, and Sezary syndrome.

Heterophilic antibodies in human serum can react with reagent immunoglobulins, interfering with in vitro immunoassays. Patients routinely exposed to animals or to animal serum products can be prone to this interference and anomalous values may be observed.

Test method: Chemiluminescence.


TOTAL IgG

Immunoglobulins, classified as IgA, IgD, IgE, IgG and IgM, play important roles in disease pathogenesis, diagnosis, prevention and therapy. Quantitative immunoglobulin measurements can monitor the course of a disease and its treatment. IgG constitutes 70-75% of total immunoglobulins in blood.

Serum IgG levels are decreased in several hereditary and aquired IgG immunodeficiencies and also in combined cell-mediated and antibody immunodeficiencies. IgG levels are also decreased in conditions like protein- losing syndromes, pregnancy, non-IgG myeloma. Selective deficiency of one or more IgG subclasses is associated with a variety of recurrent infections or Asthma.

Elevated levels of IgG may be found in IgG Myeloma, Chronic liver disease, autoimmune diseases, parasitic diseases and chronic infection.

Test Technique: Nephelometry


TOTAL IgM
Immunoglobulins classified as IgA, IgD, IgE, IgG and IgM, play important roles in disease pathogenesis, diagnosis, prevention and therapy. Quantitative immunoglobulin measurements can monitor the course of a disease and its treatment.

Measurement of immunoglobulin M is useful in the diagnosis of hereditary and acquired IgM immunodeficiencies. Total IgM evaluates humoral immunity; establishes the diagnosis and monitors therapy in macroglobulinemia of Waldenstrom and Plasma cell myeloma. IgM levels are used to evaluate likelihood of in utero infections or acuteness of infections.

Total IgM levels may be decreased in protein-losing syndromes, non-IgM myeloma, infancy and early childhood.

Elevated levels of IgM are associated with liver disease and chronic infections.

Test Technique: Nephelometry


TOTAL PROTEIN, SERUM

Test Technique: Biuret


TOTAL PROTEIN,ALBUMIN,GLOBULIN RATIO

Test Technique: Biuret, serum blank, end point / Calculation

TOTAL T3, SERUM
Triiodothyronine (3,5,3'-L-triiodothyronine, T3) is a hormone that originates from direct thyroid synthesis and secretion (approximately 20%) and from peripheral conversion of T4 to T3 (approximately 80%). T3 is secreted into the circulation in response to the pituitary hormone TSH (Thyroid Stimulating Hormone). The secretion of T3 is regulated by a negative feedback mechanism involving the thyroid gland, pituitary gland and hypothalamus. Although serum levels of T3 are small, it has a greater physiological potency than T4.
In the circulation, 99.7% of T3 is reversibly bound to transport proteins, primarily thyroxine-binding globulin (TBG) and to a lesser extent albumin and thyroxine-binding prealbumin (TBPA). Unbound or Free T3 is metabolically active and bound T3 is metabolically inactive, acting as a reserve for Free T3.
TBG concentrations remain relatively constant in healthy individuals. However, pregnancy, excess estrogens, androgens, anabolic steroids and glucocorticoids are known to alter TBG levels and may cause false thyroid values for thyroid function tests. T3 levels in these situations may not accurately reflect thyroid status.
Primary malfunction of the thyroid gland may result in excessive (hyper) or below normal (hypo) release of T3 or T4. In addition, as TSH directly affects thyroid function, malfunction of the pituitary or the hypothalamus influences the thyroid gland activity. Disease in any portion of the thyroid-pituitary-hypothalamus system may influence the levels of T3 and T4 in the blood.
Diagnostically, T3 concentration is more sensitive to certain thyroid conditions than T4. While T4 levels are a sensitive (and superior) indicator of hypothyroidism, T3 blood levels better define hyperthyroidism.
In addition, in the Euthyroid Sick Syndrome multiple alterations in serum thyroid function test findings have been recognized in patients with a wide variety of nonthyroidal illness (NTI) without evidence of preexisting thyroid or hypothalamic-pituitary disease.

Below mentioned are the guidlines for Pregnancy related reference ranges for Total T3
---------------------------------------------------------------------------------------------------------
Levels in TOTAL T3
Pregnancy (ng/dL)
First Trimester 105 - 230
2nd Trimester 129 - 262
3rd Trimester 135 - 262
-------------------------------------------------------------------------------------------------------
Below mentioned are the guidelines for age related reference ranges of T3:
Age Reference Range Units
0-6 days 73 – 288 ng/dl
6 days-3 months 80 - 275 ng/dl
3-12 months 86 - 265 ng/dl
1-6 years 92 – 248 ng/dl
6-11 years 93 – 231 ng/dl
11-20 years 91 – 281 ng/dl

Reference:
1. Burtis C.A., Ashwood E. R. Bruns D.E. Teitz textbook of Clinical Chemistry and Molecular Diagnostics, 4th Edition.
2. Gowenlock A.H. Varley's Practical Clinical Biochemistry, 6th Edition.
3. Behrman R.E. Kilegman R.M., Jenson H. B. Nelson Text Book of Pediatrics, 17th Edition

Test method: Chemiluminescence


TOTAL T3, SERUM

Triiodothyronine (3,5,3'-L-triiodothyronine, T3) is a hormone that originates from direct thyroid synthesis and secretion (approximately 20%) and from peripheral conversion of T4 to T3 (approximately 80%). T3 is secreted into the circulation in response to the pituitary hormone TSH (Thyroid Stimulating Hormone). The secretion of T3 is regulated by a negative feedback mechanism involving the thyroid gland, pituitary gland and hypothalamus. Although serum levels of T3 are small, it has a greater physiological potency than T4.

In the circulation, 99.7% of T3 is reversibly bound to transport proteins, primarily thyroxine-binding globulin (TBG) and to a lesser extent albumin and thyroxine-binding prealbumin (TBPA). Unbound or Free T3 is metabolically active and bound T3 is metabolically inactive, acting as a reserve for Free T3.

TBG concentrations remain relatively constant in healthy individuals. However, pregnancy, excess estrogens, androgens, anabolic steroids and glucocorticoids are known to alter TBG levels and may cause false thyroid values for thyroid function tests. T3 levels in these situations may not accurately reflect thyroid status.

Primary malfunction of the thyroid gland may result in excessive (hyper) or below normal (hypo) release of T3 or T4. In addition, as TSH directly affects thyroid function, malfunction of the pituitary or the hypothalamus influences the thyroid gland activity. Disease in any portion of the thyroid-pituitary-hypothalamus system may influence the levels of T3 and T4 in the blood.

Diagnostically, T3 concentration is more sensitive to certain thyroid conditions than T4. While T4 levels are a sensitive (and superior) indicator of hypothyroidism, T3 blood levels better define hyperthyroidism.

In addition, in the Euthyroid Sick Syndrome multiple alterations in serum thyroid function test findings have been recognized in patients with a wide variety of nonthyroidal illness (NTI) without evidence of preexisting thyroid or hypothalamic-pituitary disease.

Below mentioned are the guidlines for Pregnancy related reference ranges for Total T3
---------------------------------------------------------------------------------------------------------
Levels in TOTAL T3
Pregnancy (ng/dL)
First Trimester 81 - 190
.
2nd Trimester 100 - 260
.
3rd Trimester 100 - 260
-------------------------------------------------------------------------------------------------------

Below mentioned are the guidelines for age related reference ranges of T3:
Age Reference Range Units
Cord Blood 30 - 70 ng/dl
New Born 75 - 260 ng/dl
1 - 5 year 100 - 260 ng/dl
5 - 10 years 90 - 240 ng/dl
10 - 15 years 80 - 210 ng/dl

Reference:
1. Burtis C.A., Ashwood E. R. Bruns D.E. Teitz textbook of Clinical Chemistry and Molecular Diagnostics, 4th Edition.
2. Gowenlock A.H. Varley's Practical Clinical Biochemistry, 6th Edition.
3. Behrman R.E. Kilegman R.M., Jenson H. B. Nelson Text Book of Pediatrics, 17th Edition

Test method: Chemiluminescence

TOTAL T4, SERUM
Thyroxine (3,5,3'-L-tetraiodothyronine T4) is a hormone synthesized and secreted by the thyroid gland and plays an important role in regulating metabolism. T4 is secreted into the circulation in response to the pituitary hormone TSH (Thyroid Stimulating Hormone). The secretion of T4 is regulated by a negative feedback mechanism involving the thyroid gland, hypothalamus and pituitary gland.
In the circulation, 99.95% of T4 is reversibly bound to transport proteins, primarily thyroxine-binding globulin (TBG) and to a lesser extent albumin and prealbumin. Unbound or Free T4 is metabolically active and bound T4 is metabolically inactive, acting as a reserve.
TBG concentrations remain reasonably constant in healthy individuals. However, pregnancy, excess estrogens, androgens, anabolic steroids and glucocorticoids are known to alter TBG levels and may cause false thyroid values for thyroid function tests. Altered T4 level in these situations may not accurately reflects thyroid status.
Primary malfunction of the thyroid gland may result in excessive (hyper) or below normal (hypo) release of T3 or T4. In addition, as TSH directly affects thyroid function, malfunction of the pituitary or the hypothalamus influences the thyroid gland activity. Disease in any portion of the thyroid-pituitary-hypothalamus system may influence the levels of T4 and T3 in the blood.
In addition, in the Euthyroid Sick Syndrome multiple alterations in serum thyroid function test findings have been recognized in patients with a wide variety of nonthyroidal illness (NTI) without evidence of preexisting thyroid or hypothalamic-pituitary disease.

Below mentioned are the guidlines for Pregnancy related reference ranges for Total T4.
---------------------------------------------------------------------------------------------------------
Levels in TOTAL T4
Pregnancy (µg/dL)
First Trimester 6.6 - 12.4
2nd Trimester 6.6 - 15.5
3rd Trimester 6.6 - 15.5
-------------------------------------------------------------------------------------------------------
Below mentioned are the guidelines for age related reference ranges of T4:
Age Reference Range Units
1 - 3 days 8.2 - 19.9 µg/dl
1 week 6.0 - 15.9 µg/dl
1 - 12 Months 6.1 - 14.9 µg/dl
1 - 3 years 6.8 - 13.5 µg/dl
3 - 10 years 5.5 - 12.8 µg/dl

Reference:
1. Burtis C.A., Ashwood E. R. Bruns D.E. Teitz textbook of Clinical Chemistry and Molecular Diagnostics, 4th Edition.
2. Gowenlock A.H. Varley's Practical Clinical Biochemistry, 6th Edition.
3. Behrman R.E. Kilegman R.M., Jenson H. B. Nelson Text Book of Pediatrics, 17th Edition

Test method: Chemiluminescence


TOTAL TSH, SERUM
Thyroid-stimulating hormone is a glycoprotein with two non-covalently bound subunits. TSH is synthesized and secreted by the anterior pituitary in response to a negative feedback mechanism involving concentrations of FT3 (Free T3) and FT4 (Free T4). Additionally, the hypothalamic tripeptide, thyrotropin-releasing hormone (TRH), directly stimulates TSH production. TSH interacts with specific cell receptors on the thyroid cell surface and exerts two main actions. The first action is to stimulate cell reproduction and hypertrophy. Secondly, TSH stimulates the thyroid gland to synthesize and secrete T3 and T4. The ability of quantitate circulating levels of TSH is important in evaluating thyroid function. It is especially useful in the differential diagnosis of primary (thyroid) from secondary (pituitary) and tertiary (hypothalamic) hypothyroidism. In primary hypothyroidism, TSH levels are significantly elevated, while in secondary and tertiary hypothyroidism, TSH levels are low. TRH stimulation differentiates secondary and tertiary hypothyroidism by observing the change in patient TSH levels. Typically, the TSH response to TRH stimulation is absent in cases of secondary hypothyroidism and normal to exaggerated in tertiary hypothyroidism. TSH assays with increased sensitivity and specificity provide a primary diagnostic tool to differentiate hyperthyroid from euthyroid patients.

Below mentioned are the guidelines for Pregnancy related reference ranges for TSH
---------------------------------------------------------------------------------------------------------
Levels in TSH
Pregnancy (µIU/mL)
First Trimester 0.3 - 4.5
2nd Trimester 0.5 - 4.6
3rd Trimester 0.8 - 5.2
-------------------------------------------------------------------------------------------------------
Below mentioned are the guidelines for age related reference ranges of TSH:
Age Reference Range Units
Birth - 4 days 1.0 - 38.9 µIU/mL
2 - 20 Weeks 1.7 - 9.1 µIU/mL
20 weeks - 20 years 0.7 - 6.4 µIU/mL

Reference:
1. Burtis C.A., Ashwood E. R. Bruns D.E. Teitz textbook of Clinical Chemistry and Molecular Diagnostics, 4th Edition.
2. Gowenlock A.H. Varley's Practical Clinical Biochemistry, 6th Edition.
3. Behrman R.E. Kilegman R.M., Jenson H. B. Nelson Text Book of Pediatrics, 17th Edition

Test method: CHEMILUMINESCENCE


TOXOCARA ANTIBODY, ELISA (SERUM)

Interpretative Criteria:
<1.00 Antibody Not Detected
> or = 1.00 Antibody Detected
Results of this assay must be interpreted with caution, as broad variations in antibody response occur, and levels may remain elevated for years after infection. Further, as with many parasitic serology assays, antibodies induced by other parasitic infections may crossreact in this assay.
Although a negative result (<1.00) usually rules out infection with Toxocara spp., parallel testing of serial samples may prove useful in following patients with suspected Toxocara infection.

TOXOPLASMA ANTIBODIES, SERUM
Toxoplasmosis is caused by an obligate intracellular protozoa Toxoplasma gondii. Acquired Toxoplasmosis is usually asymptomatic and benign. In pregnant women, however, the infection may enter the foetal circulation by Trans-placental route and cause congenital Toxoplasmosis. The risk and severity of congenital Toxoplasmosis is greatest when acquired during first three months of pregnancy. The consequences of Congenital Toxoplasmosis range from Spontaneous Abortion and Prematurity to generalized and neurological symptoms.

Positive levels:
A positive result for IgG antibodies indicates past infection & protection. Women with positive IgG titres before pregnancy should not be restrained from pregnancy. However, repeat IgG titres may be subscribed in all the trimesters. IgA and IgM- Antibodies specific to Toxoplasma are elevated in acute phase. IgA antibodies rapidly decline in two to three months whereas IgM antibodies persist and are better indicator of recent infection. Simultaneous presence of IgM & IgG antibodies helps in determining approximate time of onset of the infection.

Negative levels:
Negative Toxoplasma IgG indicates absence of infection. Negative Toxoplasma IgG may be observed in immuno- compromised patients. Patients with low levels of positivity should get re- tested for IgG. Increased levels of positivity for Toxoplasma IgG suggest reactivation of the disease.

RECOMMENDATIONS:
Paired testing of acute and convalescent phase sera is recommended, if clinically indicated. Please provide the SRL Ranbaxy Laboratories accession number of the specimen when submitting follow-up sera. The sera will be tested simultaneously to optimize the utility of the results. All sera are stored frozen for six weeks for additional testing. SRL Ranbaxy strongly recommends simultaneous testing of maternal and infant sera, if clinically indicated for suspected CNS Toxoplasmosis.

Test method: Enzyme Immuno-Assay.


TOXOPLASMA GONDII PCR

Clinical Utility:
Toxoplasma gondii is an obligate intracellular parasite commonly infecting a variety of mammals including rodents, domestic housecats and humans. Primary infection or reactivation of T. gondii occurs in an immunocompromised host, the clinical sequelae can be severe and potentially life threatening as for e.g. toxoplasmosis encephalitis (TE).
Infection acquired during pregnancy can lead to congenital infection in the fetus and potentially serious birth defects.
Serological diagnosis of active toxoplasmosis is often difficult due to high prevalence of Toxoplasma IgG antibodies and persistence of IgM antibodies even after 1 year of infection or in case of absence of IgM in immunocompromised patients.
Moreover diagnosis of acute central nervous system, intrauterine or congenital toxoplasmosis is also difficult by serological methods, and direct detection of the virus in CSF and amniotic fluid by stains or culture is unreliable.
PCR offers rapid and most sensitive option for detection of T. gondii DNA in CSF or amniotic fluid for detection of acute TE and intrauterine or congenital infection.

Interpretation:
Nested PCR is done to target conserved gene of T. gondii. A clinical sample is considered to be T. gondii DNA PCR positive if the PCR test (single and /or nested PCR) is positive. A detection of T. gondii DNA in blood, CSF or other body fluids suggests active infection. In addition, the presence of T. gondii DNA in amniotic fluid, fetal tissue and neonatal specimens strongly suggests active and/or congenital infection.

Limitations :
PCR is a highly sensitive technique; common reasons for paradoxical results are contamination during specimen collection, selection of inappropriate specimens and inherent PCR inhibitors in the specimen.

Test technique: Nested Polymerase chain reaction

Toxoplasma gondii is a ubiquitous intracellular parasite causing serious infections in humans and domesticated animals. Toxoplasma infection is asymptomatic in vast majority of immunocompetent individuals and is different from toxoplasmosis, the clinical or pathological disease. Latent (chronic infection) ensues in all infected people after resolution of the acute phase, due to asymptomatic persistence of the parasite. Reactivation of latent infection is usually seen in severly immunocompromised individuals.Toxoplasma infection acquires a special significance in pregnant women, as the parasite may enter the foetal circulation by transplacental route and cause congenital toxoplasmosis. The risk and severity of congenital toxoplasmosis is greatest when acquired during first three months of pregnancy. The consequences of congenital toxoplasmosis range from spontaneous abortion and prematurity to generalised and neurological symptoms. Hence accurate diagnosis and dating of the duration of maternal toxoplasmosis is required in order to assess the risk of subsequent congenital infection.

A positive Toxoplasma IgM result may not always indicate a primary acute infection, as IgM has a tendency to persist, even at high levels, after primary infection. False-positive IgM results may occur due to rheumatoid factor and antinuclear antibodies. Hence, IgG avidity testing is recommended to differentiate between primary infection, IgM persistence and reactivation.

Avidity is defined as the functional binding strength of antibodies to multiple binding sites (epitopes) on the antigen. The test is based on the principle that antibodies formed in response to primary infection have relatively low avidity to the corresponding antigen. With time, a broader antibody response develops with antibodies being formed to more epitopes on the antigen and with a corresponding increase in the antibody antigen avidity. Therefore, when a secondary antibody response occurs with reinfection, it stimulates clonal expansion of memory B cells to a much wider spectrum of epitopes ,producing antibodies of considerably greater avidity.

A positive IgM accompanied by low-avidity IgG is suggestive of a primary infection, whereas a high-avidity IgG indicates either IgM persistence or reactivation. A low avidity index may also be seen in a proportion of infected persons for months. Hence it is advised to perform IgM testing initially to point to the need for IgG avidity to avoid misinterpretation of results

Test method: Enzyme Immuno- Assay"


TOXOPLASMA IgG, SERUMToxoplasma gondii is a ubiquitous intracellular parasite causing serious infections in humans and domesticated animals. Toxoplasma infection is asymptomatic in vast majority of immunocompetent individuals and is different from toxoplasmosis, the clinical or pathological disease. Latent (chronic infection ) ensues in all infected people after resolution of the acute phase ,due to asymptomatic persistence of the parasite. Reactivation of latent infection is usually seen in severly immunocompromised individuals.
Acquired Toxoplasmosis is usually asymptomatic and benign in pregnant women. However, the infection acquires a special significance as the parasite may enter the foetal circulation by transplacental route and cause congenital toxoplasmosis. The risk and severity of congenital toxoplasmosis is greatest when acquired during first three months of pregnancy. The consequences of congenital toxoplasmosis range from spontaneous abortion and prematurity to generalised and neurological symptoms.
Toxoplasma specific IgM develops two to four weeks after the onset of clinical signs and gradually declines hereafter, disappearing in three to nine months. Therefore, the presence of IgM and IgA in the absence of IgG or in the presence of low IgG levels is a strong evidence of acute toxoplasmosis. Conversely, the presence of IgM in the presence of decreasing or constant IgG levels indicates subacute infection.
Specific IgG antibodies to Toxoplasma rise gradually and peak two to five months after the onset of clinical signs. Therefore, the presence of IgG is useful in distinguishing subjects who have acquired the disease from those who have not. This is particularly important in order to adopt suitable prophylaxis in susceptible women of child-bearing age. Increased levels of Toxoplasma specific IgG suggest reactivation of the disease. IgG may be falsely negative in immunocompromised patients
On account of the diversity or absence of symptoms, the detection of Toxoplasma infection has to be based not on clinical findings, but on serology. Also, accurate dating of the duration of maternal toxoplasmosis is required in order to assess the risk of subsequent congenital infection. However, positive IgM results are not easy to interpret, because specific IgM has a tendency to persist, even at high levels, after primary infection. False-positive IgM results may occur due to rheumatoid factor and antinuclear antibodies.
Hence, IgG avidity testing is recommended to differentiate between primary infection, IgM persistence and reactivation. A positive IgM accompanied by low-avidity IgG is suggestive of a primary infection, whereas a high-avidity IgG indicates either IgM persistence or reactivation. A low avidity index may also be seen in a proportion of infected persons for months. Hence it is advised to perform IgM testing initially to point to the need for IgG avidity to avoid misinterpretation of results

Test method: Enzyme Immuno- Assay


TOXOPLASMA IgM, SERUM

Toxoplasma gondii is a ubiquitous intracellular parasite causing serious infections in humans and domesticated animals. Toxoplasma infection is asymptomatic in vast majority of immunocompetent individuals and is different from toxoplasmosis, the clinical or pathological disease. Latent (chronic infection ) ensues in all infected people after resolution of the acute phase ,due to asymptomatic persistence of the parasite. Reactivation of latent infection is usually seen in severly immunocompromised individuals.
Acquired Toxoplasmosis is usually asymptomatic and benign in pregnant women. However, the infection acquires a special significance as the parasite may enter the foetal circulation by transplacental route and cause congenital toxoplasmosis. The risk and severity of congenital toxoplasmosis is greatest when acquired during first three months of pregnancy. The consequences of congenital toxoplasmosis range from spontaneous abortion and prematurity to generalised and neurological symptoms.
Toxoplasma specific IgM develops two to four weeks after the onset of clinical signs and gradually declines hereafter, disappearing in three to nine months. Therefore, the presence of IgM and IgA in the absence of IgG or in the presence of low IgG levels is a strong evidence of acute toxoplasmosis. Conversely, the presence of IgM in the presence of decreasing or constant IgG levels indicates subacute infection.
Specific IgG antibodies to Toxoplasma rise gradually and peak two to five months after the onset of clinical signs. Therefore, the presence of IgG is useful in distinguishing subjects who have acquired the disease from those who have not. This is particularly important in order to adopt suitable prophylaxis in susceptible women of child-bearing age. Increased levels of Toxoplasma specific IgG suggest reactivation of the disease. IgG may be falsely negative in immunocompromised patients
On account of the diversity or absence of symptoms, the detection of Toxoplasma infection has to be based not on clinical findings, but on serology. Also, accurate dating of the duration of maternal toxoplasmosis is required in order to assess the risk of subsequent congenital infection. However, positive IgM results are not easy to interpret, because specific IgM has a tendency to persist, even at high levels, after primary infection. False-positive IgM results may occur due to rheumatoid factor and antinuclear antibodies.
Hence, IgG avidity testing is recommended to differentiate between primary infection, IgM persistence and reactivation. A positive IgM accompanied by low-avidity IgG is suggestive of a primary infection, whereas a high-avidity IgG indicates either IgM persistence or reactivation. A low avidity index may also be seen in a proportion of infected persons for months. Hence it is advised to perform IgM testing initially to point to the need for IgG avidity to avoid misinterpretation of results

Test method: Enzyme Immuno- Assay.


TRIGLYCERIDES, NON-FASTING, SERUM
Triglycerides have been traditionally tested in fasting condition and account for > 90% of dietary intake & 9.5% of fat stored in tissues. Increased TG levels are seen in coronary heart disease, atherosclerotic disease, liver disease, alcoholism, Nephrotic syndrome, hypothyroidism, pancreatitis, gout, glycogen storage disease, fatty liver and familial hyper trigyceridemias.

An increasing body of medical evidence is now supporting the evaluation of non fasting triglyceride levels as a direct marker for cardiovascular disease risk (1). A high level of non fasting triglycerides coincides with increased levels of remnant lipoproteins in the blood after a meal (2). These fat remnants promote arterial wall damage and atherosclerosis (2). Fasting triglyceride levels may miss this information; hence the non fasting triglyceride test could independently predict the risk of myocardial infarction and ischemic heart disease (3).

There is no established reference range for non fasting triglycerides hence the reported value for this parameter does not carry the same. Documented evidence however suggests that 90% of normal healthy individuals have a non-fasting triglyceride of less than 159.48 mg/dl, which is a little above the acceptable range even for fasting. Studies have also shown that 75% of males have non fasting triglyceride levels below 221.5 mg/dl and females below 150.62 mg/dl during the day (4). Non fasting triglycerides > 443 mg/dl predict, respectively 3 and 4 fold increase in risk of ischemic stroke in men and women in the general population (5).

Test method: Spectrophotometry

1. Borge G. Nordestgaard et al. Nonfasting Triglycerides and Risk of Myocardial Infarction, Ischemic Heart Disease, and Death in Men and Women. JAMA. 2007; 298 (3):299-308.
2. Sandeep Bansal et al. Fasting Compared with Nonfasting Triglycerides and Risk of Cardiovascular Events in Women. JAMA 2007; 298(3):309-316.
3. Paul M Ridker. Fasting versus Nonfasting Triglycerides and the Prediction of Cardiovascular Risk: Do We Need to Revisit the Oral Triglyceride Tolerance Test? Clin Chem. 2008 Jan;54(1):11-3.
4. van Wijk JP, van Oostrom AJ, Castro Cabezas.
Normal ranges of non-fasting triglycerides in healthy Dutch males and females. M Clinica chimica acta 337(1-2):49-57, 2003 Nov
5. Jacob J Freiberg, Anne Tybjaerg-Hansen, Jan S Jensen, Borge G Nordestgaard. Nonfasting triglycerides and Risk of Ischemic Stroke in the General Population. Circulation. 2008; 118:S-756.


TRIGLYCERIDES, SERUM

Triglycerides, Cholesterol & lipoprotein fractions (VLDL, LDL & HDL) levels are interpreted collectively. Disturbances may be primary or secondary.

Test Technique: Enzymatic


"Testing was performed at Metropolis, Mumbai. This test is not covered under the scope of accreditation of NABL and CAP of SRL"


TROPONIN I

Troponin I is a part of three subunit complex comprising of Troponin T, Troponin C along with tropomyosin. After cardiac injury, Troponin I is released into the blood 4 - 6 hrs after the onset of the pain and remains elevated for 6 - 10 days. cTnI release has also been documented in cardiac conditions other than acute myocardial infarction (AMI) such as unstable angina, congestive heart failure, and ischemic damage due to coronary artery bypass surgery. The minimum detection level of the kit used is 0.5 ng/mL. A negative result at any time does not preclude the possibility of myocardial infarctio


URIC ACID, 24HRS URINE

Test method: Spectrophotometry


URIC ACID, SERUM

Test Technique: Uricase


CULTURE, URINE

Urine specimens received for culture are examined microscopically and cultured also carrying out colony counts for the same.

Standard Criterion of active bacterial infection of urinary tract is a count equal to or greater than 1,00,000 CFU/ML. A rigid adherance to the above guideline should be avoided and culture counts should be interpreted in relation to the clinical information about the patient.
Bacterial counts in urine are influenced by various factors like high fluid intake, use of alkalinizing of acidifying agents and prior/inadequate antibiotic therapy. Therefore, a low bacterial count, should be considered possibly or probably significant in symptomatic patients.


VDRL, CSF

Test method: Flocculation reaction


VDRL, SERUM


VDRL detects antibodies found in early Syphilis, but can be non- reactive in later stages. Biologic false positives are common in a variety of other infections, Rheumatic diseases and Auto- Immune disorders. More specific Treponema Pallidum Hemagglutination assay (TPHA) test is recommended for confirmation. False negative reactions can occur in stages of the disease where there is minimal tissue damage, particularly in early infection and in latent stages.

Test method: Flocculation reaction


VITAMIN B12 LEVEL, SERUM


Vitamin B12 or cyanocobalamin is a complex corrinoid compound containing four pyrrole rings that surround a single cobalt atom. Humans obtain Vitamin B12 exclusively from animal dietary sources, such as meat, eggs and milk. Vitamin B12 requires intrinsic factor, a protein secreted by the parietal cells in the gastric mucosa for absorption. Vitamin B12 and intrinsic factor from a complex that attaches to receptors in the ileal mucosa, where proteins known as trans-cobalamins transport the Vitamin B12 from the mucosal cells to the blood and tissues. Most Vitamin B12 is stored in the liver as well as in the bone marrow and other tissues.

Vitamin B12 and Folate are critical to normal DNA synthesis, which in turn affects erythrocyte maturation. Vitamin B12 is also necessary for myelin sheath formation and maintenance. The body uses its B12 stores very economically, reabsorbing Vitamin B12 from the ileum and returning it to the liver so that very little is excreted.

Clinical and laboratory findings for B12 deficiency includes neurological abnormalities, decreased serum B12 levels and increased excretion of methylmalonic acid. The impaired DNA synthesis associated with Vitamin B12 deficiency causes macrocytic anemias. These anemias are characterized by abnormal maturation of erythrocyte precursors in the bone marrow, which results in the presence of megaloblasts and in decreased erythrocyte survival.

Pernicious anemia is a macrocytic anemia caused by Vitamin B12 deficiency that is due to lack of intrinsic factor. Low Vitamin B12 intake, gastrectomy, and diseases of the small intestine, malabsorption and trans-cobalamin deficiency can also cause Vitamin B12 deficiency.

Preservatives such as fluorides & ascorbic acid interfere with this assay. Excessive exposure of the specimen to light may alter Vitamin B12 result.

Test method: Chemiluminescence.

WBC ABSOLUTE COUNT

HEMATOLOGY


WEIL-FELIX TEST, SERUM
The Weil Felix test is a heterophile agglutination test used for the diagnosis of rickettsial diseases. Rickettsiae are small gram negative bacilli and are transmitted to humans by arthropod vectors. They mainly cause 2 groups of diseases in humans-typhus fevers and spotted fevers. The typhus fever group consists of epidemic typhus, recrudescent typhus (Brill Zinsser Disease) and endemic typhus, while the spotted fevers mainly include tick typhus and Rocky Mountain spotted fever.
The basis of the test is the sharing of a carbohydrate antigen by some rickettsiae and certain strains of Proteus species (P.vulgaris OX 19, 2 & P. mirabilis OX K). The test measures the antibodies against the OX 19, OX 2 & OX K antigens of Proteus strains, in the patients' sera. The test is performed in serially increasing dilutions to obtain a titre. A titre of upto 1:80 can be seen in normal human sera and can be as high as 1:160 with proteus OXK suspension.
Agglutination patterns for several rickettsial diseases are shown in the following table:
Infection............................................Vector...............................Proteus Suspension
................................................................................................OX19............OX2........OXK
------------------------------------------------------------------------------------------------------------
Epidemic Typhus................................Louse...........................+++.................+...............-
Murine Typhus....................................Flea..............................+++.................+...............-
Endemic Typhus.................................Flea..............................+++.................+...............-
Rocky Mountain Spotted Fever.........Tick..............................+++.................+...............-
Tsutsugamushi Fever............ ...........Mite.................................-....................-..............+++
Scrub Typhus.................................... Mite.................................-....................-…..........+++
Boutonneuse Fever............................Tick..................................+...................+................+
South African Tick-bit Fever........... Tick..................................+...................+.................+
Brill Zinsser Disease........................Louse.......................Usually -…..Usually -..Usually -
Trench Fever.....................................Louse................................-.....................-.................-
Q Fever.............................................Tick...................................-.....................-.................-
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Antibodies appear rapidly during the course of disease, reach peak titres by the second week and then decline rapidly during convalescence. Therefore a high titer is a useful indication of recent infection.
False positive reactions may occur in patients with infections with Proteus spp and other unrelated conditions such as Malaria, Typhiod, Infectious Mononucleosis, Brucellosis, Tuberculosis or Narcotic Addiction etc. Thus all results must be interpreted in the context of clinical findings. Also, paired testing of acute phase and convalescent phase samples (10- 14 days after first sample) is recommended. A rise in titre between the 2 sera is considered diagnostic of rickettsial infection.

Test method: Tube Agglutination method.


WIDAL TEST, SERUM

The Widal agglutination test is used for diagnosing Enteric Fever. The term enteric fever includes typhoid fever caused by Salmonella typhi, Salmonella paratyphi A, B and C. Though enteric fever is endemic in all parts of
India, S. paratyphi C infections are uncommon and are not included in Widal testing.
The Widal test measures the antibodies against the 'H' (flagellar) & 'O' (somatic) antigens of typhoid and paratyphoid(A & B) bacilli ,in the patients sera. The test is performed in serially increasing dilutions. Agglutination in dilution 1:160 is suggestive of Salmonella infection. Agglutination in dilutions of and more than 1:320 is confirmatory of Enteric Fever. The causative organism is determined by species specific 'H' antigen showing significant titre. Agglutination in dilution up to 1:80 may be seen in normal individuals residing in endemic areas.
The titre of the Widal test will depend on the stage of the disease. Antibodies usually appear by the beginning of second week of infection. Hence blood taken earlier may give a negative result. The titre increases steadily till the 3rd or 4th week after which it declines gradually. Cases treated early with antibiotics may show a poor antibody response.
Individuals who have suffered from past Salmonella infection may show mild to moderate increase in titre during an unrelated fever (anamnestic response). Similarly, persistent antibody titres (especially against more than one 'H' antigens) may be seen in individuals vaccinated against Enteric Fever. Also, false positive results may be occasionally seen in other diseases such as tuberculosis, pneumonia, amoebiasis, rickettsial disease, Rheumatoid arthritis, hepatitis B etc due to cross reacting antigens. Hence paired testing of acute phase and convalescent phase samples (10- 14 days after first sample) is recommended. A four fold rise in titre between the 2 sera is considered diagnostic of enteric fever.
Please note that the baseline/diagnostic Widal titres differ for each geographical area .Hence the test result must be interpreted in light of the same.

Since the Widal test is diagnostically useful only beyond the 2nd week of infection, Blood Culture and/or Rapid Typhoid IgM testing are recommended for early diagnosis of infection.

Test method: Agglutination Test

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