Also known as: Gamma Glutamyl Transferase, Gamma GT, GGT, Glutamyl Transpeptidase, GT.

The enzyme GT is found in many organs, including the kidney, liver, spleen and pancreas; however, the main source of GT in the blood is the liver. Gamma-glutamyl transferase (GGT) levels can be used to determine the cause of an elevated alkaline phosphatase (ALP). Both ALP and GT are elevated in disease of the bile ducts and in certain liver diseases, but only ALP will be elevated in bone disease. If the GT level is normal in a person with a high ALP, the cause is probably bone disease.