ALP vs GGT — what's the difference?
ALP is found in liver, bone, and intestine. GGT is liver-specific. ALP elevation with normal GGT suggests bone source; ALP with GGT suggests cholestatic liver disease.
Full answer
ALP (alkaline phosphatase) and GGT (gamma-glutamyl transferase) are both used to evaluate cholestatic liver patterns, but they have different tissue distributions. ALP is found in liver, bone, intestine, and placenta — so elevations can come from non-hepatic sources, especially bone. GGT is essentially liver-specific. The pairing answers the question: elevated ALP with elevated GGT = cholestatic liver disease; elevated ALP with normal GGT = bone source (workup for vitamin D deficiency, Paget's, metastasis). GGT is also sensitive (though non-specific) for alcohol-related hepatic impact.
Educational. Not a substitute for individualized provider review.
- ALT — Primary source · oMeds
- Reviewed by Dr. Laura Purdy, MD, MBA · Clinical Director, oMeds · Last reviewed 2026-05-29