Calculators & Tools

King's College Criteria — Paracetamol ALF

Predicts poor prognosis in paracetamol-induced acute liver failure - indication for transplant referral.

1 What is the King's College Criteria — Paracetamol ALF?

The King's College Criteria — Paracetamol ALF is a GI & Liver scoring tool used in paediatric practice. Predicts poor prognosis in paracetamol-induced acute liver failure - indication for transplant referral. It scores 5 criteria and interprets the total across 3 bands, so the number always arrives with the severity it implies rather than on its own. In PediAid each criterion is shown as a labelled option with the weight it carries, so the total can be checked rather than taken on trust.

2 When to use it

  • Grading severity at the bedside in GI & Liver
  • Recording an objective severity band in the case notes
  • Deciding when a total crosses the threshold for escalation
  • Re-scoring to track whether a child is improving or deteriorating
  • Checking the exact criteria of a score used infrequently

3 Formula & method

The score sums 5 criteria: Arterial pH < 7.30 after adequate fluid resuscitation; Arterial lactate > 3.0 mmol/L after fluid resuscitation; INR > 6.5 (prothrombin time > 100 s); Serum creatinine > 3.4 mg/dL (300 µmol/L); Grade III-IV hepatic encephalopathy. Totals are then banded: any score - Criteria not met: transplant criteria not met on current values. Continue N-acetylcysteine and supportive care; repeat assessment - parameters can evolve rapidly; 3 criteria or more - Criteria MET: all three of INR >6.5, creatinine >3.4 mg/dL and grade III-IV encephalopathy - poor prognosis. Refer urgently to a liver transplant centre; 4 criteria or more - Criteria MET: pH <7.30 (or lactate >3.0) after resuscitation - poor prognosis independent of other values. Refer urgently to a liver transplant centre.
  • Criteria are met by EITHER: arterial pH <7.30 (or lactate >3.0 after resuscitation) alone, OR all three of INR >6.5, creatinine >3.4 mg/dL and grade III-IV encephalopathy.
  • Source: O’Grady JG et al. Early indicators of prognosis in fulminant hepatic failure. Gastroenterology 1989;97:439-45.

4 Frequently asked questions

How many criteria does the King's College Criteria — Paracetamol ALF use?

5. They are Arterial pH < 7.30 after adequate fluid resuscitation; Arterial lactate > 3.0 mmol/L after fluid resuscitation; INR > 6.5 (prothrombin time > 100 s); Serum creatinine > 3.4 mg/dL (300 µmol/L); Grade III-IV hepatic encephalopathy.

What do the bands of the King's College Criteria — Paracetamol ALF mean?

The total is interpreted as: any score - Criteria not met: transplant criteria not met on current values. Continue N-acetylcysteine and supportive care; repeat assessment - parameters can evolve rapidly; 3 criteria or more - Criteria MET: all three of INR >6.5, creatinine >3.4 mg/dL and grade III-IV encephalopathy - poor prognosis. Refer urgently to a liver transplant centre; 4 criteria or more - Criteria MET: pH <7.30 (or lactate >3.0) after resuscitation - poor prognosis independent of other values. Refer urgently to a liver transplant centre.

Does the score replace clinical judgement?

No. It is a structured way to record and communicate severity. A clinician concerned about a child should act on that concern regardless of the total.

Where does this score come from?

Criteria are met by EITHER: arterial pH <7.30 (or lactate >3.0 after resuscitation) alone, OR all three of INR >6.5, creatinine >3.4 mg/dL and grade III-IV encephalopathy.

Does it work offline?

Yes. Score definitions are bundled with the PediAid app, so the score computes without a connection.

For qualified clinicians. This page and the PediAid app are a clinical aid only. Calculations and reference data must be verified against the patient's clinical context, the source guideline and your local protocols before any treatment decision is made.