Gamma Glutamyltransferase In Serum
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Reference-interval
- Male & Female: 3.0 - 59.0 U/L
Principle
- The Kodak Ektachem Clinical Chemistry Slide (GGT) is a dry, multilayered analytical element coated on a clear polyester support.
- An 11 uL drop of sample is deposited on the slide & evenly distributed by the spreading layer. GGT catalyzes the transfer of the delta-glutamyl moiety of L-gamma-glutamyl-p-nitroanilide to glycylglycine, simultaneously producing p-nitroaniline. The rate change in reflection density is measured & is used to calculate the enzyme activity of GGT.
- The reaction sequence involved:
* L-gamma-glutamyl-p-nitroanilide GGT p-nitroaniline * + Glycylglycine (Gly-Gly) -------> + gamma-glutamyl-GlyGly
Clinical-significance
- gamma-Glutamyltransferase plays a major role in glutathione metabolism & in resorption of amino acids from the glomerular filtrate. It is also important in the absorption of amino acids from the intestinal lumen. GGT is found mainly in the liver, pancreas & kidney, although lower activities can be demonstrated in most other organs.
- Serum GGT is a sensitive indicator of hepatobiliary disease & is useful in the diagnosis of obstructive jaundice, chronic alcoholic liver disease, in the follow-up of chronic alcoholics undergoing treatment, & in the detection of hepatotoxicity. GGT is more responsive to biliary obstruction than AST, ALT or ALP. GGT is also increased in hepatoma, carcinoma of the pancreas, and carcinoma metastatic to the liver.
Increases
- hepatobiliary disease & biliary obstruction (largest increases)
- inflammation
- cirrhosis
- space-occupying lesions
- infectious mononucleosis
- renal transplant
- hyperthyroidism
- myotonic dystrophy
- diabetes mellitus
- pancreatitis
- alcohol-induced liver disease
- pregnancy
- prostate cancer
- lipoid nephrosis (mild)
- pharmaceutical agents
- GGT is a useful marker for: (level reflect recurrence)
- High levels of GGT is found in the urine of patients with urinary tract infection & with destruction of renal tissue.
- Risk factor:
- may be risk factor for cardiovascular disease [5,6] may reflect oxidative stress [6]
Specimen
- No special patient preparation required.
- Heparin & EDTA may be used as anticoagulants for plasma specimens. No special patient preparation is necessary. Collect the specimen by the standard venipuncture technique.
- Remove serum from the clot & analyze as soon as possible.
- Sodium fluoride/ potassium oxalate should not be used as anticoagulants.
- Hemolyzed specimens should not be used.
- Ensure equipment is free from soap or glycerol contamination. Collection tubes with glycerol-lubricated stoppers should not be used.
- Refrigerate specimen if it cannot be analyzed immediately. Freeze specimen for long-term storage or shipment.
- Minimum sample required is 0.5 milliliter with an optimum size of 1.0 milliliter or larger.
More General Terms
Additional Terms
References
- Kodak Ektachem 700 Analyzer Operator's Manual, Kodak Clinical Products, Rochester, New York.
- Kodak Ektachem Slide Package Inserts, Kodak Clinical Products Rochester, New York.
- Kodak Ektachem Training Manual, Kodak Clinical Products, Rochester, New York.
- Clinical Guide to Laboratory Tests, 3rd ed. Teitz ed., W.B. Saunders, 1995
- Ruttmann E et al, Gamma-glutamyltransferase as a risk facotr for cardiovascular disease mortality: and epidemiologic investigation in a cohort of 163,944 Austrian adults Circulation 2005; 112:2130 PMID: [1]
- Sakuta H et al, Gamma-glutamyltransferase and metabolic risk factors for cardiovascular disease Intern Med 2005; 44:538 PMID: [2]
