GGT
An early-warning liver enzyme that often moves before ALT or AST.
What is it
GGT is an enzyme found in liver and bile duct cells. It is highly sensitive to bile flow problems, alcohol use, and certain medications.
Why it's measured
GGT has been studied as an early-warning marker for liver and metabolic issues, often rising before ALT or AST in research literature.
Reference range
Standard laboratory reference
< 50 U/L
Reference ranges vary by laboratory. Your individual reference range will appear on your test report and should be interpreted by your physician in the context of your overall health profile.
What results may indicate
Elevated
Has been associated with alcohol use, fatty liver disease, bile duct issues, and metabolic syndrome in research literature.
Lower
Is generally considered favorable.
These associations are general. They are not a personal diagnosis or prediction. Discuss your individual results with your physician in the context of your full health profile.
When it's measured
Part of comprehensive liver panels.
Related markers
Measured in
A complete look at your heart, hormones, metabolism, inflammation, and longevity systems — drawn at Quest or LabCorp, reviewed by a U.S.-licensed physician.
Explore the Apex Panel →This information is for general educational purposes only and is not medical advice. Lab results alone are not intended to diagnose, treat, or cure any condition and do not replace the advice of a healthcare provider. OPTML does not offer medical advice, a diagnosis, medical treatment, or any form of medical opinion.