GGT (Gamma-Glutamyl Transferase)

Sensitive to alcohol, bile duct issues, and oxidative stress.

What it is

GGT is an enzyme present in the liver and bile ducts. It is highly sensitive to alcohol consumption, bile duct obstruction, and oxidative stress — but less specific than ALT for liver cell damage.

Why it matters

Elevated GGT alongside normal ALT/AST often points to bile duct issues or lifestyle factors. In combination with ALP, it helps distinguish liver from bone causes of ALP elevation. It is also a sensitive marker of excessive alcohol use.

How to test

Standard liver function panel.

This information is for educational purposes only. Always discuss testing and interpretation of results with your care team.

Optimal range

Men: below 55 U/L. Women: below 38 U/L.

How often

Every 3–6 months. Included automatically in most comprehensive metabolic panels.