Gamma-glutamyl Transferase (GGT) Test
The GGT test measures an enzyme primarily found in the liver to help identify liver damage or bile duct blockages.
Overview
Gamma-glutamyl transferase (GGT) is an enzyme found throughout the body, but it is concentrated in the liver. When the liver or bile ducts are damaged, GGT leaks into the bloodstream. This test is often performed alongside an alkaline phosphatase (ALP) test to distinguish between liver disease and bone disorders.
What is it used for?
The GGT test is used to:
- Help diagnose liver disease.
- Determine if elevated liver enzymes are due to liver damage or bone issues.
- Check for bile duct blockages.
- Screen for or monitor alcohol use disorder (AUD), as alcohol consumption increases GGT levels.
Why do I need a GGT test?
Your provider may order this test if you show symptoms of liver disease, including:
- Fatigue and weakness
- Jaundice
- Loss of appetite
- Abdominal pain or swelling
- Nausea and vomiting
- Severe itching
What do the results mean?
Higher-than-normal levels of GGT may indicate liver damage caused by conditions such as hepatitis, cirrhosis, pancreatitis, diabetes, heart failure, or medication side effects. Generally, higher levels correlate with more significant damage.
Results are often interpreted in conjunction with ALP levels:
- High ALP and high GGT: Suggests a liver disorder.
- High ALP and normal/low GGT: Suggests a bone disorder.
Low or normal GGT levels typically indicate that liver disease is unlikely.