Maddrey Discriminant Function Calculator
Maddrey Discriminant Function Calculator
Identify severe alcohol-related hepatitis, where a discriminant function of 32 or more is the conventional threshold for corticosteroids.
Maddrey Discriminant Function
PT + bilirubinPatient PT 19.5 s, control 12.5 s, bilirubin 12 mg/dL
Formula
- PT
- prothrombin time in seconds — the control value must come from the same laboratory
- bilirubin
- mg/dL — divide µmol/L by 17.1
- 32
- the threshold defining severe disease
Worked example
Patient PT 19.5 s, control 12.5 s, bilirubin 12 mg/dL
4.6 × (19.5 − 12.5) = 4.6 × 7 = 32.2
32.2 + 12 = 44.2
≥ 32 → severe alcohol-related hepatitis
Using the result
| DF | Severity | Action |
|---|---|---|
| < 32 | Not severe | Abstinence, nutrition, treat infection |
| ≥ 32 | Severe | Consider corticosteroids after excluding sepsis and bleeding; Lille score at day 7 |
Where the discriminant function fits
Maddrey’s discriminant function was derived in the trials that first tested corticosteroids in alcohol-related hepatitis, and the threshold of 32 identifies the group in which those trials found a mortality benefit. It remains the entry criterion for steroid treatment in most guidelines, more than four decades on.
The practical trap is the prothrombin time. The formula requires PT in seconds against the reporting laboratory’s own control, and many laboratories now report only an INR. Substituting the INR gives a number that is not the discriminant function and will misclassify patients — if the control PT is not available, ask for it rather than approximating.
A high discriminant function is not by itself a reason to start steroids. Sepsis, gastrointestinal bleeding, acute kidney injury and uncontrolled hyperglycaemia all need addressing first, and active infection is a contraindication. Once treatment starts, the Lille score at day 7 determines whether to continue: a Lille above 0.45 indicates non-response, and steroids should be stopped rather than continued for a full course.
Newer scores — GAHS, ABIC and MELD — predict mortality at least as well, and many units use MELD alongside the discriminant function. None has displaced it as the treatment threshold.
Frequently asked questions
What Maddrey score is severe?
32 or above defines severe alcohol-related hepatitis, historically carrying a 28-day mortality of 30 to 50% without treatment, and is the conventional threshold for considering corticosteroids.
Can I use the INR instead of prothrombin time?
No. The formula is defined in terms of prothrombin time in seconds against a laboratory control. Substituting INR gives a different quantity and will misclassify patients.
Does a high score mean steroids should be started?
Not automatically. Sepsis, gastrointestinal bleeding and renal failure must be addressed first, and active infection is a contraindication. Response is then assessed with a Lille score at day 7.
How does it compare with MELD?
MELD and GAHS predict mortality at least as well and use standardised inputs. The discriminant function persists because the steroid trials were built on it, so guidelines still specify it as the treatment threshold.
Related calculators
References
- Maddrey WC et al. Corticosteroid therapy of alcoholic hepatitis. Gastroenterology. 1978;75(2):193–9.
- Crabb DW et al. Diagnosis and treatment of alcohol-associated liver diseases: AASLD practice guidance. Hepatology. 2020;71(1):306–33.