Gamma-GT is a sensitive liver enzyme that often rises first, even before ALAT or ASAT respond. A high gamma-GT usually points to alcohol use, bile duct problems or metabolism. That makes it a kind of early warning system for your liver.
Below you will read what gamma-GT measures, which causes are most common, and what you can do.
What is gamma-GT?
Gamma-GT (gamma-glutamyltransferase) is found mainly in the liver and bile ducts. Normal is below 55 U/L in men and below 40 U/L in women, with differences per laboratory. It is very sensitive but also non-specific: an elevation says something is going on, not immediately what.
What does an elevated gamma-GT mean?
An isolated elevation, without ALAT or ASAT rising, usually points to alcohol, medication effects or metabolic syndrome. If gamma-GT rises together with alkaline phosphatase, your doctor thinks more about the bile ducts. A complete explanation is in understanding liver values.
Causes of a high gamma-GT
- Alcohol - the most common cause of an isolated elevation.
- Gallstones or bile duct obstruction - often with an elevated alkaline phosphatase.
- Medications - anti-epileptics, oral contraceptives and some antibiotics.
- Fatty liver and metabolic syndrome - excess weight, type 2 diabetes and high cholesterol.
Gamma-GT and alcohol
Gamma-GT responds strongly to regular or heavy drinking and is often the first liver value to rise. After a period without alcohol, the value usually drops within a few weeks. That makes it a handy gauge to see the effect of cutting back.
Gamma-GT and cardiovascular disease
Interestingly, an elevated gamma-GT in large population studies is associated with a higher risk of cardiovascular disease, independent of the liver (Ruttmann et al., 2005). It is seen as a marker for oxidative stress and metabolic problems.
What can you do about a high gamma-GT?
Less or no alcohol is usually most effective. A healthy weight, exercise and limiting sugar also help. Discuss your medications with your doctor, but do not stop on your own. With the liver function test you can track your gamma-GT, with review by a doctor.
Frequently asked questions
How quickly does gamma-GT drop after stopping alcohol?
Often within 2 to 4 weeks, sometimes a little longer. The half-life is several weeks, so an alcohol-free period shows the effect well.
Can a high gamma-GT occur without alcohol?
Yes. Bile duct problems, medications, fatty liver and metabolic syndrome can also raise it. Alcohol is a common, but not the only, cause.
Is a mildly elevated gamma-GT serious?
A mild, one-time elevation is often harmless. It becomes more relevant with persistent elevation or in combination with other abnormal liver values.
References
- Ruttmann E, et al. Gamma-glutamyltransferase as a risk factor for cardiovascular disease mortality. Circulation. 2005. PubMed
- Botros M, Sikaris KA. The de Ritis ratio: the test of time. Clinical Biochemist Reviews. 2013. PubMed
- Younossi ZM, et al. Global epidemiology of nonalcoholic fatty liver disease - meta-analytic assessment of prevalence, incidence, and outcomes. Hepatology. 2016. PubMed
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