GGT (Gamma-GT)
Gamma-glutamyl transferase (GGT) is a liver enzyme found mainly in bile duct cells. It is one of the most sensitive markers of liver damage and bile duct disease. GGT is particularly elevated by alcohol consumption — even moderate drinking can raise it. It helps distinguish liver-related ALP elevation from bone-related elevation.
Reference Ranges
Male
0 – 65
U/L
Female
0 – 36
U/L
Child
0 – 25
U/L
Ages 1–18
Reference ranges may vary by laboratory. Always compare with the range printed on your lab report.
What Low Levels Mean
Low GGT is normal and indicates good liver health. There is no clinical concern with low GGT values.
What High Levels Mean
High GGT is most commonly caused by alcohol consumption (even moderate amounts), fatty liver disease, bile duct obstruction, and medications that induce liver enzymes. GGT is the most sensitive marker for alcohol-related liver damage. It is also elevated in metabolic syndrome and diabetes.
Frequently Asked Questions
Does alcohol always raise GGT?
Regular alcohol consumption (even 2–3 drinks per day) commonly raises GGT. Heavy drinkers often have GGT 2–5 times normal. However, GGT can be elevated without alcohol use — fatty liver, medications, and bile duct disease are other causes. Conversely, some heavy drinkers may have normal GGT.
How long does it take for GGT to normalize after stopping alcohol?
GGT typically normalizes within 2–6 weeks of complete alcohol abstinence, depending on the degree of elevation and underlying liver health. This makes GGT useful for monitoring alcohol abstinence in clinical settings.
Is GGT part of a standard liver function test?
Not always. Standard LFTs usually include ALT, AST, ALP, bilirubin, albumin, and total protein. GGT is often added when ALP is elevated (to determine liver vs. bone source) or when alcohol-related liver damage is suspected. Some labs include it routinely.
This information is for educational purposes only and should not replace professional medical advice. Always consult your doctor for interpretation of your test results.
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