Gamma Glutamyl Transferase (GGT)
GGT (gamma glutamyl transpeptidase) is an enzyme produced by the liver. It is used by doctors to diagnose obstructions in the biliary system, pancreatitis and liver disease. GGT may also be elevated in liver and pancreatic cancer, alcoholism, and is sometimes used as a marker for tumor progression as well as evaluating response to treatment. An 8 to 12 hour fast is required for this blood test. However, drink plenty of water and take medications as prescribed.
Special Note: Individuals taking phenytoin or phenobarbital can have falsely elevated GGT.