Gamma-glutamyl transferase (GGT) is markedly elevated in isolation in a 45-year-old asymptomatic man. ALT, AST, and ALP are normal. The most likely explanation is:

• A Chronic alcohol use inducing hepatic GGT ✓
• B Primary biliary cholangitis
• C Acute viral hepatitis A
• D Cholestatic drug reaction

Explanation

GGT is a microsomal enzyme highly inducible by alcohol and certain drugs; isolated GGT elevation with normal ALP, ALT, and AST is the classic footprint of chronic alcohol use. Primary biliary cholangitis and cholestatic reactions typically raise ALP and bilirubin alongside GGT. Acute hepatitis A preferentially raises transaminases, not GGT in isolation.

Reference: Harper's Illustrated Biochemistry, 32nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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