A gamma-glutamyl transferase (GGT) test measures the amount of GGT in the blood. GGT is an enzyme found throughout the body, but it is mostly found in the liver. When the liver is damaged, GGT may leak into the bloodstream. High levels of GGT in the blood may be a sign of liver disease or damage to the bile ducts . Bile ducts are tubes that carry bile in and out of the liver. Bile is a fluid made by the liver. It is important for digestion.
A GGT test can't diagnose the specific cause of liver disease. So it is usually done along with or after other liver function tests , most often an alkaline phosphatase (ALP) test . ALP is another type of liver enzyme. It's often used to help diagnose bone disorders as well as liver disease.
Other names: gamma-glutamyl transpeptidase, GGTP, Gamma-GT, GTP