Clinical QuickieLiver/GI
AST vs ALT
Elevated transaminases do not equal liver failure.
AST/ALT Are Injury Markers
ALT is more liver-specific; AST also comes from skeletal muscle, heart and other tissues.
Neither directly measures hepatic function.
Name the Pattern
Think hepatocellular, cholestatic or mixed by looking at AST/ALT alongside alkaline phosphatase and bilirubin.
The pattern narrows the differential before you reach for additional testing.
Context Changes the Source
Review alcohol, medications/supplements, metabolic risk, viral risk, hypotension/ischemia and muscle injury.
An AST-predominant pattern is a clue, not a diagnosis.
Function Is a Different Question
INR/PT, bilirubin, albumin and the patient's clinical status tell you more about function and severity than transaminase height alone.
Elevated enzymes and impaired function are not the same finding.
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