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Blood Test: Gamma-Glutamyl Transpeptidase (GGT)

Reviewed by: Larissa Hirsch, MD
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What Is a Blood Test?

By taking and testing a small sample of a person’s blood, doctors can check for many kinds of diseases and conditions. Blood tests help doctors check how the body’s organs are working and see if medical treatments are helpful.

To help your child get ready for a blood test, find out if they need to fast (not eat or drink) or should stop taking medicines before the test. Explain what to expect during the test. If your child is anxious about it, work together on ways to stay calm.

What Is GGT?

Gamma-glutamyl transpeptidase (GA-muh GLOO-tuh-mil trance-PEP-teh-dace), or GGT, is an enzyme found throughout the body, but especially in the liver. A high blood level of GGT can be a sign of a problem in the liver or bile ducts (which carry bile from the liver to the intestines to help digest food). If the liver is injured or irritated or the bile ducts are blocked, the enzyme can leak out of the cells and cause higher levels in the blood.

Why Are GGT Tests Done?

This test measures the level of GGT in the bloodstream. Doctors might order it if a child has signs of a possible problem with the liver or bile ducts, such as jaundice (yellowish skin or eyes), dark pee, light-colored poop, nausea, vomiting, or belly pain.

It also might be done if a child is on medicine that can cause problems with the liver or bile ducts, or if the results of another liver enzyme test showed a possible problem.

What if I Have Questions?

If you have questions about the GGT test, or what the test results mean, speak with your doctor. 

Reviewed by: Larissa Hirsch, MD
Date reviewed: November 2022