Maddrey's Discriminant Function Calculator

The calculation utilizes a specific formula that weighs abnormalities in coagulation and hepatic excretion. The mathematical equation is expressed as: d_function = 4.6 * (pt - pt_control) + bilirubin. In this formula, pt represents the patient's prothrombin time measured in seconds, pt_control represents the laboratory reference control time, and bilirubin is measured in mg/dL. A resulting score greater than 32 indicates severe alcoholic hepatitis associated with a high short-term mortality rate, guiding clinicians toward proactive treatment options.

Consider a patient presenting with acute alcoholic hepatitis symptoms. Their lab results show a serum bilirubin level of 10.0 mg/dL, a prothrombin time (pt) of 20 seconds, and a laboratory control prothrombin time (pt_control) of 12 seconds. First, find the difference in prothrombin time: 20 - 12 = 8 seconds. Next, multiply this difference by the standard coefficient of 4.6: 4.6 * 8 = 36.8. Finally, add the bilirubin value: 36.8 + 10.0 = 46.8. Because the resulting discriminant function score of 46.8 exceeds the critical threshold of 32, it signals severe disease severity requiring urgent specialized management.

Always ensure that the prothrombin time and control values utilize the exact same units of measurement in seconds before entering them into the equation. Verify that bilirubin values are accurately converted into mg/dL to maintain mathematical consistency. Remember that this calculator serves as a supportive screening instrument and should always be interpreted alongside a comprehensive physical examination and complete metabolic panel evaluated by a qualified healthcare provider.