GGT (Gamma glutamyltransferase)

The purpose of this blood serum chemistry test is to provide information about hepatobiliary diseases, to assess liver function, and to detect alcohol ingestion. Another purpose is to distinguish between skeletal disease and hepatic disease when serum alkaline phosphatase is elevated.

Normal results in females under age 45, range from 5 to 27 U/L; in females over age 45 and in males, levels range from 6 to 37 U/L. 

A normal GGT level suggests such elevation stems from skeletal disease. Serum GGT values vary with the assay method used (colorimetric or kinetic). The sharpest increases in GGT levels indicate obstructive jaundice and hepatic metastasis. Elevations may indicate any acute hepatic disease, acute pancreatitis, renal disease, alcohol ingestion, postoperative status, and prostatic metastasis. This test is nonspecific, providing little data about the type of hepatic disease. GGT is particularly sensitive to the effects of alcohol in the liver, and levels may be elevated after moderate alcohol intake and in chronic alcoholism, even without clinical evidence of hepatic injury.