King's College Criteria for Non-Paracetamol Acute Liver Failure
The King's College criteria for non-paracetamol acute liver failure requiring urgent liver transplantation are: INR >6.5 (PT >100 seconds) OR any three of the following five variables: age <10 or >40 years, non-A/non-B hepatitis, halothane hepatitis, drug-induced liver injury, or jaundice-to-encephalopathy interval >7 days.
The Specific Criteria
For non-paracetamol poisoning, the King's College Hospital criteria indicate poor prognosis and potential need for emergency liver transplantation when:
- INR >6.5 (or prothrombin time >100 seconds) alone, OR
- Any three of five of the following:
- Age <10 years or >40 years
- Etiology: non-A, non-B hepatitis, halothane hepatitis, or idiosyncratic drug reaction
- Jaundice to encephalopathy interval >7 days (indicating subacute liver failure)
- INR >3.5
- Bilirubin >300 μmol/L (>17.5 mg/dL)
Performance Characteristics and Clinical Context
The King's College criteria have good specificity (82%) but limited sensitivity (68%) for predicting mortality in non-paracetamol acute liver failure 1. This means they are better at identifying who will survive than who will die without transplantation.
Critical performance nuances:
- Specificity is highest (93%) when applied to patients with high-grade hepatic encephalopathy (grade III-IV) 1
- Dynamic application through the clinical course improves specificity to 88% 1
- Sensitivity has decreased in modern studies (58% post-2005 vs 85% pre-1995), suggesting improved medical management allows more patients to survive without transplantation 1
Comparative Accuracy
A meta-analysis comparing prognostic models found that for non-paracetamol acute liver failure, MELD score (DOR 8.42) outperforms King's College criteria (DOR 4.16) in predicting mortality 2. However, King's College criteria remain widely used due to their simplicity and established track record.
Important Clinical Caveats
Encephalopathy should not be an absolute prerequisite for transplant listing 3. In certain etiologies like Amanita phalloides poisoning, patients may meet transplant criteria before developing encephalopathy.
Prothrombin index <10% (approximately INR >6) from day 4 onwards after acute liver injury has 100% accuracy for predicting fatal outcome in some studies 3.
Recent data challenges these criteria: A 2026 study found that among patients meeting King's College criteria, 58% had spontaneous liver regeneration and only 36.8% died, with one-year transplant-free survival exceeding 80% 4. This suggests the criteria may overestimate transplant need in the modern intensive care era.
Practical Application Algorithm
- Immediate assessment: Calculate INR and identify etiology
- If INR >6.5: Patient meets criteria - initiate transplant evaluation
- If INR 3.5-6.5: Assess the five variables above
- If ≥3 present: Patient meets criteria - initiate transplant evaluation
- If <3 present: Continue monitoring, reassess daily
- Apply dynamically: Reassess criteria every 24 hours as clinical course evolves
- Priority for transplant listing: Patients with high-grade encephalopathy (III-IV), autoimmune hepatitis, or seronegative hepatitis 4
Etiology-Specific Considerations
Patients less likely to need transplantation despite meeting criteria: acetaminophen-induced (92.3% spontaneous regeneration) and ischemic acute liver failure 4, 5.
Patients more likely to need transplantation: autoimmune hepatitis, seronegative hepatitis, non-paracetamol drug toxicity, and subacute liver failure 6.
All patients meeting King's College criteria should be managed in a transplant center regardless of immediate listing decision, as clinical deterioration can be rapid 7.