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King's College Criteria for acetaminophen toxicity
King's College Criteria for acetaminophen toxicity
Arterial pH (after fluid resuscitation)
pH
INR (or PT in seconds via labs)
INR
Serum creatinine
mg/dL
Grade III or IV hepatic encephalopathy
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When to use
- Deciding on liver-transplant referral in acetaminophen-induced acute liver failure.
Formula
Positive if arterial pH <7.30, OR all three of: INR >6.5 (PT >100 s), creatinine >3.4 mg/dL (300 umol/L), and grade III/IV hepatic encephalopathy.
Pearls and pitfalls
- Assess pH after adequate volume resuscitation.
- Creatinine >3.4 mg/dL corresponds to >300 umol/L.
- Meeting criteria has high specificity but limited sensitivity; not meeting them does not exclude a poor outcome.