Biomarker · Liver
Gamma-glutamyl transferase (GGT)
GGT is a liver enzyme often used to investigate bile-duct problems and alcohol-related liver stress. Learn what the test shows and what affects it.
Written by LON6EVITY Editorial Team · Last updated
Overview
GGT is an enzyme found mainly in the liver and bile ducts.
Why it matters
MedlinePlus explains that GGT is often measured to help find the cause of a raised alkaline phosphatase (ALP) and to check for liver or bile-duct damage. It is also sensitive to alcohol use.
Higher results
GGT can be raised by alcohol, fatty liver, bile-duct blockage and several medications. It is not specific to one condition.
How the test is performed
A blood sample; you may be asked to avoid alcohol and fast beforehand.
Reference ranges
Reference ranges and targets differ between laboratories, units and guidelines, and depend on age, sex, method and your overall clinical picture. A single result is not a diagnosis — interpret it with a qualified clinician.
Factors that can affect the result
- Alcohol
- Medications (e.g. some anti-seizure drugs)
- Fatty liver
- Smoking
Questions people commonly ask
- Is GGT a test for alcohol?
- It is sensitive to alcohol but not specific; other conditions and medications also raise it.
Related biomarkers
Related tests
Related topics
Understand your biomarkers in context
What does this mean for your own health data? Log your results, follow trends over time and bring an organised summary to your next doctor's appointment.
Sources
- Gamma-glutamyl Transferase (GGT) Test. MedlinePlus, U.S. National Library of Medicine.