Liver Function Tests (LFTs) on the NCLEX
AST, ALT, alk phos, bilirubin, albumin: patterns of hepatocellular vs cholestatic injury.
LFTs distinguish hepatocellular from cholestatic injury. NCLEX tests common patterns.
Hepatocellular injury
AST and ALT elevated. Causes: viral hepatitis, alcohol, drug-induced (acetaminophen, statins), ischemic. AST>ALT (2:1+) suggests alcohol.
Cholestatic injury
Alkaline phosphatase and direct bilirubin elevated. Causes: biliary obstruction (stones, tumor), drug-induced cholestasis, primary biliary cholangitis.
Synthetic function
Albumin (low = chronic), PT/INR (prolonged = acute or chronic). Both reflect liver's ability to make proteins.
Bilirubin
Total = direct + indirect. Indirect (unconjugated) elevation: hemolysis, Gilbert's. Direct (conjugated) elevation: obstruction, hepatocellular.
Frequently asked
ALT vs AST?
ALT more liver-specific. AST also in muscle, RBCs.
Mild AST/ALT elevation in obesity?
Think NAFLD. Lifestyle modification first-line.
Quick check
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