Test Name

Gamma
GT

Test Code

231

Unit

U/L

Station

Chemistry

Synonym Name/Abbreviation

Gamma Glutamyl Transferase, glutamyl transpeptidase, GGT,
GT

CPT Code

82977

Performing Facility

American Medical Labs, Herzliya
Pituah

Analyzer

Roche cobas 6000

Test Method

Enzymatic colorimetric
assay

AML Preferred Tube

5 mL SST gel

Storage Instructions

Refrigerated.

Separate serum from cells within 45 minutes;
Stability:

Up to 7 days at room temperature

or at 2 to 8 ^oC

 up to 1 year at -15 to -25 ^oC

Min. Volume

1 mL

Turn-Around-Time

One day.

Intended Use

Diagnosis and monitoring of hepatobiliary diseases. GGT is
one of tne most sensitive indicators when screening for such diseases and
also for occult alcoholism.
Useful in diagnosis of chronic alcoholic liver disease (although
some heavy drinkers do not have GT
increases)

Limitations

The combination of high alkaline phosphatase and normal GGT
does not rule out liver disease completely.  Elevated in serum of patients
long-term medicated with phenobarbital and phenytoin (such patients would
be better served with orders for one of the alternate tests = leucine
aminopeptidase (LAP) or 5′ nucleotidase). Activity not significantly
increased in  patients with
lymphoma (unless there is hepatic involvement by the lymphoma). Measuring
range: 3.0 to 1200 U/L

Patient Preparation

No preparation needed

Reasons for Rejection

Gross hemolysis, improper labeling

Adult Reference Ranges

Male: 8 to 61 U/L

 Female:5 to 36 U/L