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Free Maddrey's Discriminant Function Calculator

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Typical range is 11–13 seconds.

Enter prothrombin time and bilirubin level to calculate Maddrey's score

Alcoholic Hepatitis and the Maddrey Discriminant Function

The Maddrey’s Discriminant Function (MDF) Calculator — often called the Maddrey score calculator, MDF calculator, or alcoholic hepatitis prognosis calculator — is a free online tool that provides a rapid assessment of the short‑term prognosis for patients with alcoholic hepatitis. It requires only three simple laboratory values: the patient’s prothrombin time (PT), a reference PT, and the total serum bilirubin level.

Understanding Alcoholic Hepatitis

Alcoholic hepatitis is an acute inflammatory injury of the liver caused by heavy and sustained alcohol consumption. It can lead to substantial morbidity and mortality, particularly in middle‑aged adults. Typical signs include fatigue, anorexia, tender hepatomegaly, jaundice, and ascites. The first step in management is complete abstinence from alcohol. In more severe cases, pharmacological therapies such as corticosteroids, pentoxifylline, and N‑acetylcysteine are often used. Because the disease may range from mild to life‑threatening, early risk stratification is important. Several scoring systems exist — the Model for End‑Stage Liver Disease (MELD), the Child‑Pugh score, and the AST‑to‑Platelet Ratio Index (APRI) — but the Maddrey discriminant function is one of the oldest and most specific for alcoholic hepatitis.

The Maddrey Formula

First published by Maddrey and colleagues in 1978, the discriminant function is expressed as:

MDF=4.6(PTpatient−PTref)+bilirubin\text{MDF} = 4.6(\text{PT}_{\text{patient}} - \text{PT}_{\text{ref}}) + \text{bilirubin}

where:

  • PTpatient\text{PT}_{\text{patient}} = prothrombin time of the patient (in seconds)
  • PTref\text{PT}_{\text{ref}} = reference prothrombin time (typically 11–13 s, depending on the laboratory method)
  • bilirubin\text{bilirubin} = total bilirubin level (in mg/dL)

A score greater than 32 is accepted as the threshold for severe alcoholic hepatitis and indicates a poor short‑term prognosis. This cutoff was derived from the original study and has been validated in subsequent cohorts. Patients with MDF ≥ 32 are often considered candidates for corticosteroid treatment, although the final decision must be individualized.

Key Laboratory Parameters Explained

Prothrombin Time (PT): This test measures the speed of blood clotting via the extrinsic pathway. In liver disease, synthesis of clotting factors is reduced, causing a prolonged PT. The normal reference range is about 11–13 seconds, but it varies between laboratories. The classic Maddrey formula uses PT in seconds; some online calculators also accept the PT ratio or INR, but the original equation is based on seconds.

Bilirubin: Bilirubin is a yellow pigment produced during the breakdown of heme from aged red blood cells. The liver normally conjugates and excretes bilirubin; when damaged, bilirubin accumulates, leading to jaundice. Normal total bilirubin is generally less than 1.2 mg/dL (≈20 μmol/L). Most free online Maddrey calculators allow you to input bilirubin in either mg/dL or μmol/L and perform the conversion automatically.

Practical Example

Let’s compute the score for a patient with:

  • bilirubin = 2 mg/dL
  • PT = 14 s
  • reference PT = 12 s
MDF=4.6×(14−12)+2=4.6×2+2=9.2+2=11.2\begin{aligned} \text{MDF} &= 4.6 \times (14 - 12) + 2 \\ &= 4.6 \times 2 + 2 \\ &= 9.2 + 2 \\ &= 11.2 \end{aligned}

A result of 11.2 is far below the 32 threshold, indicating a favorable prognosis.

Using the Calculator in Clinical Practice

This free Maddrey’s discriminant function calculator is designed for quick, bedside use. It can help triage patients, guide discussions about steroid therapy, and provide a common language for clinicians. Nevertheless, it should never be used in isolation. The score is a prediction aid, not a definitive test. All results must be interpreted in the context of the full clinical picture, including imaging, other laboratory tests, and the patient’s overall condition. Always consult a healthcare professional before making treatment decisions.

Selected Supporting Studies

  • Maddrey WC, et al. Corticosteroid Therapy of Alcoholic Hepatitis. Gastroenterology, 1978.
  • Soultati AS, et al. Prognostic value of Maddrey’s discriminant function in alcoholic hepatitis. 2006.
  • Kadian M, et al. Comparison of MELD and Maddrey score in alcoholic hepatitis. 2014.

FAQ

1. What does the Maddrey discriminant function calculator do?

It calculates a score that estimates the severity and short‑term prognosis of alcoholic hepatitis, helping to identify patients who might benefit from corticosteroid therapy.

2. What three numbers do I need to use the calculator?

You need the patient’s prothrombin time (PT), a reference prothrombin time (normally 11–13 seconds), and the total bilirubin level (in mg/dL or μmol/L).

3. How is the Maddrey score interpreted?

A score above 32 suggests severe alcoholic hepatitis and a poor short‑term prognosis. It indicates that the patient may need more aggressive management, including corticosteroids.

4. Can I rely on the Maddrey score alone for diagnosis?

No. The Maddrey score is a prognostic tool, not a diagnostic test. It should be used together with a doctor’s clinical assessment and other laboratory results.

How to Use

  1. Enter the patient's prothrombin time in seconds.
  2. Enter the reference prothrombin time (typical range 11–13 seconds) and the bilirubin level.
  3. View the calculated Maddrey's Discriminant Function score and prognosis interpretation.