Medical AIMaddrey discriminant function calculator
The Maddrey discriminant function (mDF) grades the severity of alcohol-associated hepatitis from the prothrombin time prolongation and total bilirubin. A value of 32 or above identifies severe disease with high short-term mortality and is the classic threshold for considering corticosteroid therapy.
How to measure each input
- Patient prothrombin time
- The patient's prothrombin time in seconds. Because the formula uses the difference from a control PT, use a result from the same laboratory and assay as the control value.
- Control prothrombin time
- Your laboratory's reference / control prothrombin time in seconds. INR is not interchangeable here, as the function was derived from PT in seconds against a control.
- Total bilirubin
- Total serum bilirubin in mg/dL (the calculator converts umol/L by dividing by 17.1). It is added directly to the weighted PT term.
Interpretation
| Band | Meaning |
|---|---|
| < 32, non-severe | Non-severe alcohol-associated hepatitis with lower short-term mortality (roughly 90 percent 30-day survival). Corticosteroids are generally not indicated; focus on alcohol cessation and supportive care. |
| >= 32, severe | Severe alcohol-associated hepatitis with high 30-day mortality (often 30 to 50 percent untreated). Consider corticosteroids if there is no contraindication (active infection, GI bleeding, renal failure), and reassess steroid response at day 7 with the Lille score. |
Pitfalls, exclusions and caveats
- The result depends on the difference between patient and control PT, so mixing values from different assays or labs (or substituting INR) can materially change the score.
- mDF identifies who to consider for corticosteroids but does not confirm benefit. Steroid response is reassessed at day 7 using the Lille score; a Lille score above 0.45 suggests non-response and a case to stop steroids.
- Corticosteroids are contraindicated by active uncontrolled infection, gastrointestinal bleeding, and significant renal failure, so a high mDF does not automatically mean treatment.
- The diagnosis of alcohol-associated hepatitis must be established first; mDF grades severity, it does not diagnose the condition.
- Newer scores (MELD, MELD-Na, the Glasgow alcoholic hepatitis score, ABIC) are often used alongside mDF, as each has different sensitivity for mortality.
mDF = 4.6 x (patient prothrombin time - control prothrombin time, in seconds) + total bilirubin in mg/dL.The discriminant function was described by Maddrey et al. (1978) and later modified (the factor 4.6). This implementation is an educational tool and is not affiliated with the original authors or any guideline body.
Frequently asked
What Maddrey score means severe alcohol-associated hepatitis?
A discriminant function of 32 or above defines severe disease with high 30-day mortality, and is the classic threshold for considering corticosteroid therapy when there is no contraindication.
Can I use INR instead of prothrombin time?
No. The Maddrey function was derived from the prothrombin time in seconds compared with a laboratory control, not the INR. Substituting INR gives an invalid score.
How does the Maddrey score relate to the Lille score?
Maddrey selects patients to start corticosteroids (mDF >= 32). The Lille score is then calculated after about 7 days of steroids to judge response: a Lille score above 0.45 indicates non-response and supports stopping treatment.
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