What Does GGT Mean on a Liver Blood Test?

What it means

GGT stands for gamma-glutamyl transferase, an enzyme found mainly in the liver and bile ducts, with smaller amounts in the kidneys and pancreas. When liver or bile duct cells are under strain, more GGT leaks into the blood.

GGT is often added to liver function tests. It is very sensitive, meaning it rises easily, but it is not specific, meaning it does not point to one cause. Doctors find it most useful alongside ALP. If both are raised, the liver or bile ducts are the likely source; if ALP is high but GGT is not, bone becomes a more likely source. GGT can also rise with regular alcohol use and with some medicines, such as certain anti-seizure drugs.

GGT is different from ALT and AST. Those enzymes mostly reflect injury to liver cells, while GGT is more tied to the bile ducts and to substances the liver is processing.

Where you may see it

• Liver function test panels, sometimes as an add-on line
• Results from workplace or insurance health checks
• Notes from liver clinics or follow-up after a medicine change