Maddrey’s Discriminant Function Calculator (alcohol-related hepatitis severity)

Understanding the Maddrey's discriminant function calculator — concept and principle

Maddrey's discriminant function (DF) grades the severity of alcohol-related hepatitis from two blood tests: prothrombin time and bilirubin. It has been used for decades to identify patients with a high short-term risk of death who may benefit from corticosteroids.

Clotting + bilirubin: with the default inputs the result is DF 58 (32 or more → severe).

How it is calculated

DF = 4.6 × (patient prothrombin time − control prothrombin time) + total bilirubin (mg/dL)

Prothrombin times are in seconds; the control value comes from the laboratory.
Bilirubin in µmol/L is divided by 17.1 to give mg/dL.
A DF of 32 or more is classed as severe.

The principle

In alcohol-related hepatitis the inflamed liver makes fewer clotting factors, so the prothrombin time lengthens, and it clears less bilirubin, so jaundice deepens. Both reflect how much liver function is lost. Maddrey's original 1978 formula was modified in 1989 to the 4.6 coefficient now in use, and the threshold of 32 separated patients with a high early mortality from those with a better outlook.

Worked example

Default inputs: patient PT 22 s, control PT 12 s, bilirubin 12 mg/dL.

Prothrombin part = 4.6 × (22 − 12) = 46.
DF = 46 + 12 = 58.
58 ≥ 32 → Severe (32 or more).

Each point is the calculator re-run with only “Patient’s prothrombin time (seconds)” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Patient’s prothrombin time (seconds)	Maddrey discriminant function
5.5	-17.9
11	7.4
16.5	32.7
22	58
27.5	83.3
33	108.6
44	159.2

How to read the result

Where does your result fall?

A DF of 32 or more marks severe disease. In the early studies, untreated patients in this group had a short-term mortality of around 30–50% at one month, and it is the usual threshold for considering corticosteroids if there are no contraindications such as active infection or bleeding. Below 32 the short-term outlook is much better. Many centres also use the MELD score, and the Lille score after a week of treatment.

Common mistakes

Using the INR instead of prothrombin time in seconds.
Entering bilirubin in µmol/L while the unit is set to mg/dL.
Forgetting that the result depends on the laboratory's prothrombin reagent.

Keep in mind: This is a decision aid for clinicians, not a diagnosis or treatment advice. Alcohol-related hepatitis is a serious illness that needs specialist care.

Frequently asked questions

What Maddrey score is severe?

32 or more.

Is MELD better than Maddrey?

MELD uses INR, bilirubin and creatinine and is less dependent on the lab reagent; both are used.

Can the score improve?

Yes, with abstinence and treatment the liver can recover, and the score falls.

Sources: Maddrey WC, Boitnott JK, Bedine MS, et al., "Corticosteroid therapy of alcoholic hepatitis", Gastroenterology 1978;75:193–199 · Carithers RL Jr, Herlong HF, Diehl AM, et al., "Methylprednisolone therapy in patients with severe alcoholic hepatitis", Ann Intern Med 1989;110:685–690

Checked 9 Nov 2026. Maddrey WC et al., Gastroenterology 1978;75:193–199 and the modified 4.6 coefficient (Carithers RL et al., Ann Intern Med 1989;110:685–690) — formula and the 32 threshold as standard values.

Your numbers