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.