Enter the patient’s prothrombin time, control prothrombin time, and serum bilirubin level into the calculator to determine the Maddrey Score. This calculator can also evaluate any of the variables given the others are known.

Maddrey Score Formula

The following formula is used to calculate the Maddrey Discriminant Function, also known as the Maddrey Score.

MS = 4.6 * (PT - control PT) + serum bilirubin level


  • MS is the Maddrey Score

  • PT is the patient’s prothrombin time (seconds)

  • control PT is the standard control prothrombin time (seconds)

  • serum bilirubin level is the patient’s serum bilirubin level (mg/dL)

To calculate the Maddrey Score, subtract the control prothrombin time from the patient’s prothrombin time. Multiply the result by 4.6. Then add the patient’s serum bilirubin level to this product. The resulting score is used to assess the severity of alcoholic hepatitis. A score of 32 or higher indicates severe disease and may necessitate medical intervention such as corticosteroid therapy.

What is a Maddrey Score?

The Maddrey Discriminant Function, commonly known as the Maddrey Score, is a clinical tool used to assess the severity and prognosis of alcoholic hepatitis, a form of liver inflammation caused by excessive alcohol consumption. It is calculated using the patient’s prothrombin time (or international normalized ratio, INR) and serum bilirubin level. A score equal to or greater than 32 indicates severe alcoholic hepatitis and is associated with a high mortality rate, suggesting the potential need for corticosteroid therapy or other forms of treatment to reduce inflammation and support liver function.

How to Calculate Maddrey Score?

The following steps outline how to calculate the Maddrey Score.

  1. First, determine the patient’s prothrombin time (PT) in seconds.
  2. Next, determine the control prothrombin time (CPT) in seconds.
  3. Then, determine the patient’s serum bilirubin level in mg/dL.
  4. Next, gather the formula for the Maddrey Score: Maddrey Score = 4.6 x (PT – CPT) + serum bilirubin level.
  5. Finally, calculate the Maddrey Score by inserting the variables into the formula.
  6. After calculating the result, interpret the score to assess the severity of alcoholic hepatitis.

Example Problem:

Use the following variables as an example problem to test your knowledge.

Prothrombin time (PT) = 18 seconds

Control prothrombin time (CPT) = 12 seconds

Serum bilirubin level = 10 mg/dL

Now, calculate the Maddrey Score using the formula provided.

Maddrey Score = 4.6 x (PT – CPT) + serum bilirubin level

Maddrey Score = 4.6 x (18 – 12) + 10

Maddrey Score = 4.6 x 6 + 10

Maddrey Score = 27.6 + 10

Maddrey Score = 37.6

With a Maddrey Score of 37.6, the patient has a severe form of alcoholic hepatitis and may require specific medical interventions.