Kings College Criteria Calculator

The Kings College Criteria has been developed to evaluate the degree of multiorgan dysfunction from acetaminophen-induced liver failure, and so to help with predicting positive or poor prognosis in case of liver transplantation, in the case of patients with fulminant hepatic failure (FHF).

Kings College Criteria

Acetaminophen toxicity	Non-Acetaminophen toxicity
Criteria met if Arterial pH < 7.30 OR/AND All 3 of the below present: ˗ INR > 6.5 (PT > 100 sec) ˗ Serum Creatinine 3.4 mg/dL (301 µmol/L) ˗ Grade III or IV encephalopathy Additionally: Hyperlactemia and/or Hyperphosphatemia are a strong predictor of poor prognosis for survival without transplantation.	Criteria met if INR > 6.5 (PT > 100 sec) OR/AND 3 of the below 5 present: ˗ Age lower than 10 or greater than 40 ˗ Aetiology: Non-A, Non-B hepatitis, idiosyncratic drug reactions ˗ Duration of jaundice before development of encephalopathy > 7 days ˗ Prothombin time (PT) greater than 50 seconds (approx INR >3.5) ˗ Serum bilirubin > 18 mg/dl (300 µmol/L)

Kings College Criteria Explained

The criteria were first described by O’Grady et al. in 1989 based on a retrospective analysis of 588 patients with acute liver failure. The criteria were stratified into parameters linked to acetaminophen and non-acetaminophen causes of acute liver failure, parameters which were found to correlate with prognosis in each cause.

Acute liver failure was defined as onset of encephalopathy or coagulopathy within 26 weeks of liver disease diagnosis. Severely ill patients have high mortality risks without adequate management, which may include liver transplantation, hence why the need for a tool that can screen patients who would have positive outcomes after transplantation.

Acetaminophen toxicity	Non-Acetaminophen toxicity
Criteria met if Arterial pH < 7.30 OR/AND All 3 of the below present: ˗ INR > 6.5 (PT > 100 sec) ˗ Serum Creatinine 3.4 mg/dL (301 µmol/L) ˗ Grade III or IV encephalopathy* Additionally** Hyperlactemia and/or Hyperphosphatemia are a strong predictor of poor prognosis for survival without transplantation.	Criteria met if INR > 6.5 (PT > 100 sec) OR/AND 3 of the below 5 present: ˗ Age lower than 10 or greater than 40 ˗ Aetiology: Non-A, Non-B hepatitis, idiosyncratic drug reactions ˗ Duration of jaundice before development of encephalopathy > 7 days ˗ Prothombin time (PT) greater than 50 seconds (approx INR >3.5) ˗ Serum bilirubin > 18 mg/dl (300 µmol/L)

*Hepatic encephalopathy grades can be described as:

Grade 1 – inverted sleep pattern, agitation, forgetfulness, irritability, apraxia;
Grade 2 – lethargy, time and/or place disorientation, personality change, ataxia;
Grade 3 – somnolence with reusability, place disorientation, asterixis, hyperactive reflexes;
Grade 4 – coma

**The addition of lactate or phosphate thresholds to the criteria may improve sensitivity and negative predictive value.

Some of the limitations of the KCC to note:

PT values may not be comparable across different laboratory reagents;
The criteria may overpredict mortality in severely ill patients;
The criteria is specific but not sensitive so lack of fulfilment of criteria may still carry a poor outlook.

The table below summarizes statistical characteristics of KCC parameters for acetaminophen toxicity, including lactate (> 3.5 mmol/L after early resuscitation, or > 3.0 mmol/L after full resuscitation) and phosphate (> 3.7 mg/dL between 48 – 96 hours):

Criteria	Arterial pH < 7.30	PT, Creatinine, HE grade	Lactate	Phosphate
Positive Predictive Value	.95	.67	n/a	1
Sensitivity	.49	.45	.81	.89
Specificity	.99	.94	.95	1
Predictive Accuracy	.81	.83	.92	.98

References

Original reference

O'Grady JG, Alexander GJ, Hayllar KM, Williams R. Early indicators of prognosis in fulminant hepatic failure. Gastroenterology. 1989; 97(2):439-445.

Validation

Bailey B, Amre DK, Gaudreault P. Fulminant hepatic failure secondary to acetaminophen poisoning: a systematic review and meta-analysis of prognostic criteria determining the need for liver transplantation. Crit Care Med. 2003; 31(1):299-305.

Other references

Bernal W, Donaldson N, Wyncoll D, Wendon J. Blood lactate as an early predictor of outcome in paracetamol-induced acute liver failure: a cohort study. Lancet. 2002; 359(9306):558-563.

Schmidt LE, Dalhoff K. Serum phosphate is an early predictor of outcome in severe acetaminophen-induced hepatotoxicity. Hepatology. 2002; 36(3):659-665.

Kings College Criteria