Liver Function Tests: What the Panel Actually Shows
Content last reviewed 2026-09-12 · Educational information — not medical advice
Quick answer
Despite the name, liver panels measure DAMAGE (enzymes ALT/AST/ALP), FUNCTION (albumin, bilirubin, clotting factors), or both — patterns across them localize disease better than any single value. CMP includes six liver lines automatically.
Decoding the enzyme trio
- ALT — liver-specific leak marker; elevation = hepatocyte irritation (fatty liver #1 cause in America)
- AST — liver AND muscle/heart source; AST:ALT ratio >2 hints alcohol etiology
- ALP±GGT — bile-duct lining enzymes; together they flag cholestasis (blockage/PBC/drugs)
Function versus damage — the critical distinction
Enzymes leaking proves irritation; SYNTHETIC function proves capacity: albumin (liver-made protein) and PT/INR (clotting factors) reveal whether the factory still produces. Cirrhosis shows normal enzymes with failing synthesis sometimes — advanced disease hides behind pretty enzyme lines. Bilirubin bridges both worlds (processing capacity).
Common patterns and their signatures
| Pattern | Signature | Think |
|---|---|---|
| Hepatocellular | ALT/AST dominant | viral hepatitis, fatty liver, alcohol, drugs, ischemia |
| Cholestatic | ALP+GGT dominant ± bilirubin | stones, strictures, PBC/PSC, drug cholestasis |
| Mixed | both elevated | drug reactions, infiltrative disease |
| Isolated mild ALT bump | <2× upper limit | fatty liver usually; repeat before workup |
Workup flow after abnormal panels
Repeat in 4–8 weeks (transients normalize) → ultrasound with elastography → viral serologies (Hep A/B/C), iron studies, autoimmunity screen → medication/supplement audit including green-tea-extract and bodybuilding products — the modern hidden hepatotoxin gallery.
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Frequently asked questions
Can you have cirrhosis with normal liver enzymes?
Tragically yes — burned-out cirrhosis loses inflammatory activity; synthetic function and imaging tell late-stage truth.
Do detox teas help liver values?
Some contain actual hepatotoxins (green tea extract concentrates) — stopping dubious supplements improves panels; adding them worsens histories.