Maddrey's Discriminant Function

Maddrey's Discriminant Function is used to arrive at a prognosis in patients with alcoholic hepatitis:

4.6 [PT (patient) - PT (control)] + Total Bilirubin (mg/dl)

Where PT is prothrombin time, the time required for a blood sample to clot. Prothrombin time is important because clotting factors II, VII, IX, X are dependent on hepatic production of Vitamin K, and dysfunction in this process is the earliest indication of liver dysfunction (Dugdale 2009).

A value above 32 indicates severe alcoholic hepatitis and predicts a poor prognosis. In severe cases, this can mean the patient has a 30-day mortality rate as high as 50% (Marsano et al. 2003).