Deranged Liver Function

on call  ›  labs
reference sheet lab/lft-liver-function

Deranged Liver Function

at the bedside

  • vitals: septic, encephalopathic, or bleeding?
  • assess jaundice, asterixis, conscious level, abdominal tenderness
  • review drug chart (paracetamol, anti-TB, statins, co-amoxiclav, flucloxacillin, antiepileptics), alcohol, recent procedures
  • confirm pattern, compare with previous LFTs
escalate now if
  • INR >1.5 or rising
  • encephalopathy / asterixis
  • hypoglycaemia
  • severe jaundice · hypotension
  • Charcot’s triad (fever + jaundice + RUQ pain)

interpret the pattern

pattern at a glance
ALT / AST ↑ hepatocellular
ALP / GGT ↑ cholestatic
INR / albumin abnormal synthetic dysfunction
  • hepatocellular (ALT/AST > ALP): viral, drugs / paracetamol, ischemic (shock liver), alcohol (AST:ALT >2:1), autoimmune
  • cholestatic (ALP/GGT > ALT): obstruction (stones, tumour), drug-induced, PBC / PSC
  • mixed (both raised): drugs, sepsis, infiltration
  • isolated bilirubin (rest normal): unconjugated = Gilbert’s / haemolysis, conjugated = biliary
tools
  • R factor (ALT/ULN) / (ALP/ULN): >5 hepatocellular, <2 cholestatic, 2 to 5 mixed
  • transaminases >1000: narrow to paracetamol, ischemic hepatitis, acute viral, autoimmune

focused check

HPI
  • hepatocellular: viral risk, alcohol, drug injury, autoimmune
  • cholestatic: RUQ pain, jaundice, pale stools, dark urine, pruritus
  • chronic liver disease: ascites, GI bleeding, encephalopathy, weight loss
  • meds: paracetamol, statins, antibiotics, herbals, antiepileptics
examination
  • general: jaundice, cachexia, confusion
  • chronic liver disease: spider naevi, palmar erythema, gynaecomastia, ascites, splenomegaly
  • abdomen: hepatomegaly, RUQ tenderness, Murphy’s sign

send now

  • synthetic function: INR, albumin, glucose (define severity, not transaminases)
  • viral hepatitis serology, paracetamol level (+ timed level if overdose)
  • USS abdomen: biliary dilatation, liver texture, portal flow; MRCP if obstruction suspected
  • if cause unclear: autoimmune screen, ferritin, ceruloplasmin (selected)
if abdominal pain, add lipase
  • pancreatitis if >3× ULN with consistent pain; lipase cleaner than amylase (also rises in bowel ischemia, perforation, DKA, renal failure)

treat

  • stop the hepatotoxic drug; treat the cause
  • hepatocellular: synthetic failure discuss with the transplant centre early
  • cholestatic: USS; if obstruction, biliary decompression (ERCP); GI / hepatology review
acute liver failure
  • rising INR + falling albumin + encephalopathy + hypoglycaemia
  • urgent hepatology / ICU
  • N-acetylcysteine if paracetamol-related (start before levels if staggered or late presentation):
    • bag 1: 150 mg/kg in 200 mL glucose 5% IV over 1 h
    • bag 2: 50 mg/kg in 500 mL glucose 5% IV over 4 h
    • bag 3: 100 mg/kg in 1000 mL glucose 5% IV over 16 h
    • anaphylactoid reactions common (flushing, urticaria, bronchospasm): slow infusion, give antihistamine; do not stop NAC unless true anaphylaxis
    • follow local toxicology / pharmacy protocol for obesity dosing and treatment beyond 21 h
ascending cholangitis: Charcot’s triad
  • fever + jaundice + RUQ pain
  • IV antibiotics + urgent biliary drainage (ERCP)
new ascites + confusion in known liver disease
  • think SBP and hepatic encephalopathy: tap ascites

recheck

  • INR, albumin, glucose define severity: trend them, not just transaminases
  • repeat LFTs to confirm trend, not a single value

before leaving

  • document: pattern (hepatocellular / cholestatic / mixed), suspected cause, synthetic function
  • pending: repeat LFTs, viral serology, imaging sent
  • hand over: INR / encephalopathy trend, escalation trigger for acute liver failure
MOC pearl

transaminases give the pattern; INR, albumin and glucose give the severity. rising INR with encephalopathy = acute liver failure: call hepatology.

evidence

source type
R-factor (R-ratio) pattern classification common practice
IV N-acetylcysteine 3-bag (Prescott) protocol for paracetamol toxicity established protocol / BNF

Verify indication, dose, allergies, interactions, renal/hepatic function and local protocols before prescribing.

go deeper MOC+ Vol 4 · Acute GI & Hepatology covers this in the full reference. or the complete set.

free the on-call checklist covers the whole shift on one printable page.

More clinical resources in the MOC+ Library →

updated Sep 2026file lab/lft-liver-function