This document addresses laboratory testing of gamma glutamyl transferase (GGT) in blood.

Clinical Indications

Medically Necessary:

GGT testing using blood is considered medically necessary for any of the following indications:

1. To differentiate between sources of elevated alkaline phosphatase activity; or
2. To evaluate liver function, injury or disease in individuals with at least one of the following:
   1. Known or suspected hepatobiliary disease; or
   2. Alcohol use disorder; or
   3. Substance use disorder; or
   4. Therapy with medication that has potentially toxic effects on the liver; or
   5. Exposure to hepatotoxins; or
   6. Infections that may cause liver injury (for example, viral hepatitis, amoebiasis, tuberculosis, and similar infections); or
   7. Pancreatic disease; or
   8. Gastrointestinal disease; or
   9. Liver transplantation; or
   10. Primary or secondary malignant neoplasms; or
   11. Diseases or conditions known to have liver involvement (for example, diabetes mellitus, sarcoidosis, amyloidosis, disorders of iron and mineral metabolism, lupus, hypertension, heart failure).

Not Medically Necessary:

GGT testing using blood is considered not medically necessary when the above criteria are not met.