Gamma Glutamyl Trans (GGT) |
EPIC Test Name
GAMMA GTEPIC Code
LAB85Specimen Requirements
plasma | |
---|---|
Minimum Volume: | 0.5 mL |
Collection: | Collect specimens using standard laboratory procedures. |
Transport: | Room Temperature ASAP |
Stability: | Room Temperature: 7 days at 15-25 degrees C Refrigerated: 7 days at 2-8 degrees C Frozen: 1 year at -15 to -25 degrees C |
Container: | LT GRN |
Rejection Causes: | Hemolysis, Insufficient Sample Volume |
Methods
Enzymatic colorimetric assayTurnaround Time
Specimen | Turnaround Time | Frequency |
---|---|---|
plasma | Stat: 90 minutes Routine: 4 hours | 24/7 |
Reference Ranges
Enzymatic colorimetric assay
Male Range | Female Range | Unit |
---|---|---|
8-61 U/L | 5-36 U/L | U/L |
Clinical Indications
Gamma-glutamyltransferase (GGT) is a glycoprotein peptidase on membranes of cells with high secretory or absorptive activities. This enzyme catalyzes the transfer of the gamma-glutamyl group from peptides to an acceptor. GGT is needed for maintenance of adequate intracellular concentrations of reduced glutathione, a major antioxidant. GGT activity in serum comes primarily from the liver. Measurements of elevated serum GGT activity is a sensitive indicator of hepatobiliary disease; however, the usefulness is limited by lack of specificity.Additional Information
Increased serum GGT activity is also observed in patients receiving anticonvulsant drugs, such as phenytoin and phenobarbital, and in this setting should not be considered indicative of liver disease.Even though renal tissue has the highest concentration of GGT, normal values are observed in renal failure.
Common Synonyms
GGTPerformed
Lab |
---|
Chemistry - Downtown |
Interpretative Information
Elevated GGT activity is seen in any and all forms of liver disease with highest values seen in intra- or post hepatic biliary obstructive processes. High increases of serum GGT activity are observed in patients with primary liver neoplasms, secondary metastatic neoplasms, or other hepatic space-occupying lesions. Moderate increases (2 to 5x the upper reference limit) in activity is observed in infectious hepatitis. Smaller increases in activity are observed in more than 50% of patients with Nonalcoholic fatty liver disease (NAFLD). Increased serum GGT is found in patients with alcoholic hepatitis and is a sensitive screening test for alcoholism. Transient smaller increases are noted in cases of drug intoxication. Patients with acute and chronic pancreatitis, and in some pancreatic malignancies may also demonstrate activity 5 to 15x the upper reference limit.Serum GGT is useful in differentiating the source of increased alkaline phosphatase (ALP) to support the etiology of disease from either the liver or bone. Both an increased ALP and GGT in the serum is indicative of liver disease. An increased ALP with a normal level of GGT in the serum is indicative of bone disease.
CPT
82977LOINC
2324-2References
1. Lala V, Goyal A, Bansal P, Minter DA. Liver Function Tests. StatPearls. Treasure Island (FL): StatPearls Publishing; 2021 May-. https://www.ncbi.nlm.nih.gov/books/NBK482489/.2. Panteghini M, Bais R: Serum Enzymes. In: Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier;2018: 404-34.