Hepatology

R Factor (Liver Injury Pattern)

Hepatocellular vs cholestatic injury.

Education and reference only. Not a substitute for clinical judgement, local policy or product labelling. Always verify before clinical use. Values are calculated in your browser and never stored.

When to use

Use in abnormal liver enzymes (e.g. suspected drug-induced liver injury) to classify the pattern of injury.

Why use

It directs the differential and further work-up by injury pattern.

Critical actions

R = (ALT/ALT-ULN) ÷ (ALP/ALP-ULN). Use your lab's upper limits of normal. It classifies pattern, not severity.

Evidence & references

  1. Aithal GP et al. Case definition and phenotype standardization in drug-induced liver injury. Clin Pharmacol Ther. 2011.

Related calculators

FIB-4 IndexNon-invasive estimate of liver fibrosis.Child-Pugh ScoreSeverity and prognosis of chronic liver disease.Maddrey's Discriminant FunctionSeverity of alcoholic hepatitis.

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