Maddrey's Discriminant Function Calculator — Alcoholic Hepatitis Severity

Formula

How this is calculated

Maddrey's Discriminant Function was first published in 1978 and refined in later cohort studies. It combines two readily available laboratory values: the prolongation in prothrombin time (patient PT minus the lab's control PT, in seconds) and the total serum bilirubin in mg/dL. Each second of PT prolongation contributes 4.6 points; bilirubin in mg/dL adds directly. The formula deliberately weights coagulopathy heavily because severe synthetic dysfunction signals the degree of hepatocellular injury better than bilirubin alone.

A score of 32 or above identifies patients at high short-term mortality risk (historically 35–50% at 1 month without treatment) and is the conventional threshold at which a trial of corticosteroid therapy (prednisolone 40 mg/day for 28 days) should be considered, provided there are no contraindications such as active infection, gastrointestinal bleeding, or renal failure. Below 32, the 1-month mortality is roughly 10–15%, and the benefit of corticosteroids in this group is not established.

Limitations: MDF uses the patient's own PT rather than an INR, so results can vary across laboratories depending on the PT reagent. Alternative scores such as the MELD score, ABIC score, and the Lille model (to assess response at 7 days) are increasingly used alongside or instead of MDF. Always interpret in the clinical context of the individual patient.