King's College Criteria for Liver Transplantation in Acetaminophen Toxicity

The King's College Hospital criteria are the most widely used prognostic indicators to identify patients with acetaminophen (paracetamol)-induced acute liver failure who require urgent referral for liver transplantation. The criteria are based on arterial pH, prothrombin time/INR, serum creatinine, and grade of hepatic encephalopathy — not on the absolute transaminase level.

Analysis of the Statements

• Statement 1 (Transaminase levels > 4000 IU/L) — Incorrect: Although markedly elevated transaminases indicate hepatocellular necrosis, the degree of transaminase elevation does not correlate with prognosis and is not part of the King's College criteria. AST/ALT levels can fall even as the patient deteriorates, so they are unreliable for predicting outcome.
• Statement 2 (Acidemia: arterial/serum pH < 7.3 after adequate fluid resuscitation) — Correct: Persistent acidosis despite resuscitation is a single, independent criterion sufficient on its own to mandate transplant referral, as it reflects severe hepatocyte mitochondrial dysfunction and impending multiorgan failure.
• Statement 3 (Coagulopathy: INR > 6, i.e., prothrombin time > 100 seconds) — Correct: Severe coagulopathy is one of the three components of the combined (non-acidosis) criteria and reflects the liver's failing synthetic function.
• Statement 4 (Renal dysfunction: serum creatinine > 3.4 mg/dL) — Correct: Significant renal impairment is part of the combined criteria set, reflecting the hepatorenal involvement seen in severe acetaminophen toxicity.

The King's College Criteria (Acetaminophen-Induced Liver Failure)

A patient meets criteria for transplant referral if either:

• Arterial pH < 7.3 (after fluid resuscitation) — regardless of encephalopathy grade, OR
• All three of the following are present: INR > 6.5 (prothrombin time > 100 seconds), serum creatinine > 3.4 mg/dL, and grade III–IV hepatic encephalopathy.

Conclusion

Since acidemia, coagulopathy (INR > 6), and renal dysfunction (creatinine > 3.4 mg/dL) are the true King's College criteria components, and the transaminase level is explicitly excluded from these criteria, the correct combination is 2, 3 and 4, corresponding to option (b).