Non-clinical sciences/Lab medicine · LFT interpretation

LFT patterns — hepatocellular vs cholestatic

What it means

Hepatocellular: ALT/AST ≫ ALP — viral/autoimmune/ischaemic/drug (paracetamol) hepatitis; AST:ALT >2 + ↑GGT suggests alcohol; ALT>AST in most others. Cholestatic: ALP & GGT ≫ ALT — biliary obstruction (stones, malignancy), drugs (co-amoxiclav, flucloxacillin), PBC (AMA), PSC (UC, MRCP beading). Isolated ALP rise → check GGT to confirm hepatic (vs bone) origin.

Worked example

ALP 600, GGT 400, ALT 50, bilirubin 80 with pruritus and pale stools → obstructive/cholestatic picture.

In the exam

A jaundiced patient with pruritus and pale stools has ALP 600, GGT 420 but only mildly raised transaminases.

What settles it

Cholestatic = ALP/GGT dominant (duct problem); hepatocellular = transaminase dominant (liver-cell injury).

Classically confused with

Hepatitis B serology

Source: NICE CKS — Abnormal LFTs