Gamma-glutamyl transpeptidase (GGT) is a test to measure the amount of the enzyme GGT in the blood.

Gamma-GT; GGTP; GGT

A blood sample is needed. For information on how this is done, see: Venipuncture

The health care provider may advise you to stop taking any drugs that can affect the test.

• Drugs that can increase GGT levels include alcohol, phenytoin, and phenobarbital.
• Drugs that can decrease GGT levels include clofibrate and birth control pills.

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

This test is used to detect diseases of the liver or bile ducts. It is also done with other tests (such as the ALT, ALP, and bilirubin tests) to tell the difference between liver or bile duct disorders and bone disease.

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Gamma Results

Review Date: 02/20/2011
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)