The gamma-glutamyl transferase (GGT) test may be used to determine the cause of elevated alkaline phosphatase (ALP). Both ALP and GGT are elevated in disease of the bile ducts and in some liver diseases, but only ALP will be elevated in bone disease.
The GGT test can diagnose liver damage, but it can’t determine the cause. If your GGT level is elevated, you’ll probably have to undergo more tests.
The normal range for GGT levels is 9–48 units per liter (U/L). Normal values can vary due to age and sex.
