Maddrey Discriminant Function (DF) Calculator
Calculate the Maddrey Discriminant Function score for alcoholic hepatitis severity using prothrombin time and bilirubin. Assess 30-day mortality risk with our evidence-based medical calculator.
About This Calculator
The Maddrey Discriminant Function (DF) is a validated clinical scoring system used by hepatologists to assess the severity and short-term prognosis of alcoholic hepatitis. Originally described by Maddrey and Boitnott in 1978, this score combines two routine blood test parameters — prothrombin time and serum bilirubin — to predict 30-day mortality risk and guide treatment decisions.
The formula is: DF = 4.6 × (patient PT − control PT) + serum bilirubin (mg/dL). A score of 32 or higher identifies severe alcoholic hepatitis, which carries a 30-day mortality rate of 35–45%. Patients with DF ≥ 32 may benefit from corticosteroid therapy or pentoxifylline, though treatment decisions should always involve a multidisciplinary specialist team.
The DF is most useful when calculated within the first few days of hospitalization. It has been prospectively validated in multiple cohorts and remains the traditional model for evaluating alcoholic hepatitis severity in both clinical practice and research settings. The modified DF (using prothrombin time ratio instead of absolute difference) is an alternative formulation used in some centers.
Regional Notes
India: Alcoholic hepatitis is a common cause of liver-related hospitalization. The DF score is used alongside the Glasgow Alcoholic Hepatitis Score (GAHS) and MELD score for comprehensive risk stratification. Most Indian laboratories report PT in seconds with a control range of 11–14 seconds.
US: The American Association for the Study of Liver Diseases (AASLD) recommends the Maddrey DF for identifying patients who may benefit from corticosteroid therapy. Many US labs express PT as INR, requiring the modified DF formula.
UK: NICE guidelines endorse the DF score for assessing alcoholic hepatitis severity. UK laboratories commonly report both PT in seconds and INR. The DF should be interpreted alongside the Glasgow score and Lille model for dynamic risk assessment.
Frequently Asked Questions
What is the Maddrey Discriminant Function?
The Maddrey Discriminant Function (DF) is a scoring system used to assess the severity and prognosis of alcoholic hepatitis. It uses prothrombin time and serum bilirubin levels to predict 30-day mortality. A score of 32 or higher indicates severe alcoholic hepatitis with high mortality risk.
How is the Maddrey DF score calculated?
The formula is: DF = 4.6 × (patient prothrombin time − control prothrombin time) + serum bilirubin in mg/dL. For example, a patient with PT 20s, control PT 12s, and bilirubin 5 mg/dL would have a score of 4.6 × (20 − 12) + 5 = 41.8, indicating severe disease.
What does a DF score above 32 mean?
A DF score of 32 or higher indicates severe alcoholic hepatitis with a 30-day mortality rate of 35–45%. Patients with scores above 32 may benefit from corticosteroid therapy or pentoxifylline treatment. Immediate specialist consultation is recommended.
Can I use this calculator for diagnosis?
No. This calculator is for educational and reference purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a hepatologist or gastroenterologist for proper evaluation of alcoholic hepatitis.
What lab values do I need for this calculator?
You need the patient's prothrombin time (PT) in seconds, the laboratory control PT value in seconds, and the serum total bilirubin level in mg/dL. If your bilirubin is in µmol/L, divide by 17 to convert to mg/dL.
What is the normal prothrombin time?
Normal prothrombin time is typically 11–13.5 seconds, though reference ranges vary by laboratory. The control PT value used in the DF formula should match the laboratory-specific normal reference value.
How does DF compare to other liver scores?
The Maddrey DF is specifically designed for alcoholic hepatitis prognosis. Other liver scores include MELD (Model for End-Stage Liver Disease) for transplant prioritization and Child-Pugh for cirrhosis severity. Each score serves a different clinical purpose.
Is DF used outside of alcoholic hepatitis?
The Maddrey DF was developed specifically for alcoholic hepatitis and is not validated for other liver conditions. For non-alcoholic liver disease, scores like MELD, Child-Pugh, or NAFLD fibrosis score are more appropriate.