What Does It Mean When GGT Is High?

A GGT (Gamma-glutamyl transpeptidase) test measures liver markers to determine how well the organ is functioning. The test can also detect and monitor alcohol use.

Gamma-glutamyl transpeptidase (GGT) is a blood test that measures the level of the enzyme GGT to screen for diseases of the liver or bile ducts. 

GGT may be measured along with other tests (such as the ALT, AST, ALP, and bilirubin tests) to differentiate between liver or bile duct disorders and bone disease. 

GGT may also be used to screen for, or monitor, alcohol use.

What is the Normal Range for GGT?

The normal range of GGT for adults is 5 to 40 U/L.

What Does It Mean When GGT Is High?

High levels of GGT may indicate:

• Scarring of the liver (cirrhosis)
• Blocked flow of bile from the liver (cholestasis)
• Inflammation of the liver (hepatitis)
• Lack of blood flow to the liver
• Liver tissue death
• Liver cancer or tumor
• Use of drugs that are toxic to the liver
• Alcohol use/abuse
• Diabetes
• Heart failure
• Lung disease
• Pancreas disease
• Use of certain medications
• Phenytoin
• Phenobarbital