Recognise likelihood of different liver diseases when given the LFT patterns

Explanation:

In viral hepatitis classically the ALT is elevated with variable elevation of the AST. Usually Alk Phos and bili are normal except in severe cases.

In alcoholic liver disease, Tylenol toxicity, and ischemic hepatitis the AST is elevated more than the ALT. (AST:ALT ~ 2). GGT is a more sensitive indicator of alcohol intake thus in a patient with elevated AST but normal GGT - alcohol is unlikely to be the etiology)

Most cholestatic liver diseases have prominant elevation of the alk phos with elevation of the bilirubin in severe disease (e.g. PBC that has progressed to end-stage).

A variety of medications cause liver test abnormalities - each with it's own characteristic pattern (e.g. incr. ALT with INH, incr. Alk phos and bili with compazine)