Gamma-glutamyl Transferase (GGT) Test
A gamma-glutamyl transferase (GGT) (transpeptidase) test measures the amount of GGT in the blood.
GGT is an enzyme mainly found in the liver.
High levels of GGT in the blood may be a sign of liver disease or damage to the bile ducts.
Other names: gamma-glutamyl transpeptidase, GGTP, Gamma-GT, GTP.
GGT is an enzyme found throughout the body, but primarily in the liver. It plays a key role in the metabolism of glutathione, an important antioxidant in the body.
GGT transfers gamma-glutamyl functional groups from molecules such as glutathione to other acceptors.
GGT is most commonly used as a diagnostic marker for liver disease and alcohol consumption.
Elevated levels: Increased GGT in blood can indicate: Liver disease (hepatitis, cirrhosis, fatty liver
Bile duct obstruction
Excessive alcohol consumption
Certain medications (anticonvulsants, some antibiotics)
Pancreatic disease
Normal range: Typically 8-61 U/L for men and 5-36 U/L for women, though reference ranges may vary by laboratory.
GGT is particularly useful as a sensitive indicator of alcohol consumption and liver disease, though it’s not specific to any particular condition.