Discriminant Function Calculator - Maddrey DF Severity Score

The discriminant function calculator is a bedside clinical tool that applies the 1978 Maddrey formula to the patient's prothrombin time and total bilirubin. It returns the Maddrey Discriminant Function (MDF) score used to grade alcoholic hepatitis severity and to flag the cases where corticosteroid treatment is usually discussed.

• • Admitting an inpatient with suspected alcoholic hepatitis: A clinician on call who needs to translate a PT, control PT, and total bilirubin into a single severity band before the hepatology consult arrives.
• • Triage for steroid-discussion rounds: A pharmacist, hospitalist, or trainee preparing the steroid-decision summary and wants a consistent severity number tied to the 32-point threshold.
• • Teaching and case review: Trainees learning the difference between mild and severe alcoholic hepatitis and how the DF score connects to MELD or Lille.

Alcoholic hepatitis is a serious acute liver injury caused by heavy alcohol use. Severity drives the treatment plan, and the Maddrey DF separates mild disease (where steroids are usually avoided) from severe disease (where steroids are usually considered).

The calculator mirrors the published formula: it subtracts the reference PT from the patient's PT, multiplies the difference by 4.6, and adds the total bilirubin in mg/dL. The result is the MDF score, read against the 32-point severity band.

When the team also wants a chronic-liver-disease severity signal alongside the Maddrey score, APRI Calculator gives the AST-to-platelet ratio that hepatology often pulls from the same panel.

The calculator takes the patient PT, the control PT, and the total bilirubin in mg/dL, applies the 1978 Maddrey formula, and reads the result against the 32-point severity threshold. The output is the MDF score and a short treatment-decision prompt.

• PT_patient: Patient's actual prothrombin time in seconds from the most recent coagulation panel.
• PT_control: Reference (control) PT reported by the same laboratory in seconds; 11 to 13 seconds is a typical range.
• Total_Bilirubin: Total serum bilirubin in mg/dL. The calculator expects mg/dL, which means umol/L values should be divided by 17.1 first.
• MDF score: Maddrey 1978 discriminant function score. A result greater than 32 is treated as severe alcoholic hepatitis.

The numeric answer is a structured severity summary, not a treatment order. The calculator surfaces the band and a short clinical-review prompt so the user can see why the result crossed the threshold.

The 32-point cutoff is the threshold Maddrey and colleagues used in the original Gastroenterology paper and the threshold most downstream guidelines keep for the severe band.

According to Maddrey 1978 Gastroenterology paper, the discriminant function is 4.6 times the prothrombin time prolongation in seconds plus the total serum bilirubin in mg/dL, and a score greater than 32 marks severe alcoholic hepatitis that may benefit from corticosteroid therapy.

According to AASLD 2010 Practice Guideline on Alcoholic Liver Disease, a Maddrey score above 32 identifies patients with severe alcoholic hepatitis who should be considered for oral prednisolone 40 mg per day for 28 days, with active infection or GI bleeding reviewed before the first dose and a day-7 Lille score used to judge steroid response.

Because the discriminant function depends on the liver-function labs that usually arrive with the transaminase report, AST ALT Ratio Calculator helps interpret the AST/ALT pattern that sits next to the PT and bilirubin in the same chemistry panel.

The discriminant function combines two ideas: how well the liver makes clotting factors and how much bilirubin the liver is failing to clear.

The formula is short on purpose. Maddrey's 1978 paper wanted a single number that an admitting team could compute at the bedside with a copy of the coagulation panel.

The 32-point threshold is the value most downstream reprints keep. The calculator surfaces the band so the user can see why the result crossed the threshold.

Corticosteroid and supportive-drug decisions in severe alcoholic hepatitis still need a kidney-function review, so GFR Calculator supports the renal-function check that the admitting team usually runs alongside the MDF score.

Run the calculator from the most recent coagulation panel and the most recent total bilirubin, in that order, so the inputs match the lab report and the result is reproducible.

1. 1 Pull the patient PT and control PT: Read the patient's actual PT in seconds and the laboratory's control PT from the same report. The control value is usually 11 to 13 seconds, and 12 seconds is a safe default when the report is missing.
2. 2 Convert the total bilirubin to mg/dL: If the lab reports bilirubin in umol/L, divide by 17.1 first. The formula expects mg/dL, so 34.2 umol/L becomes 2.0 mg/dL.
3. 3 Enter the three values: Type the patient PT, the control PT, and the bilirubin into the three inputs. The calculator recomputes the MDF score as you type.
4. 4 Read the MDF score and the severity band: Look at the MDF score and the severity band. A result greater than 32 is severe; a result at or below 32 is mild to moderate.
5. 5 Document the result and the next step: Record the score, the band, and the treatment-decision context in the chart note. If the band is severe, discuss corticosteroids and plan a recheck with MELD or Lille.

A practical use: a 54-year-old admitted with jaundice after heavy drinking. The coagulation panel shows PT 19 s with a 12-second control, and the chemistry shows total bilirubin 5 mg/dL. The calculator returns MDF 37.2, which crosses the 32 threshold and lands in the severe band.

When a prolonged PT leads the team to plan fresh frozen plasma before an invasive procedure, Fresh Frozen Plasma Dose Calculator supports the volume and bag estimate that often runs in parallel to the MDF review.

The Maddrey DF can be computed by hand, but a calculator keeps the score consistent, traceable, and easier to defend at sign-out.

• • Standardised severity review across providers: Pharmacists, hospitalists, and consultants see the same MDF number and band, so the steroid-decision conversation does not depend on memory of the original Maddrey table.
• • Transparent record-keeping: The calculator records the patient PT, the control PT, and the bilirubin in the result, so a later reviewer can re-run the calculation against the same chart.
• • Quick link to the 32-point threshold: The calculator ties the score to the 32-point severe band from the Maddrey 1978 paper, which most downstream guidelines use for the steroid-discussion case.
• • Defensive handling of common input errors: The calculator clamps negative PT prolongations and surfaces the result so a transposed digit does not silently pass the threshold.

The Maddrey DF was designed to make alcoholic hepatitis severity easier to discuss. The calculator does not diagnose alcoholic hepatitis, prescribe a steroid, or replace the rest of the workup such as MELD or Lille.

The result is most useful when paired with the same reasoning the bedside team would use without the calculator.

Because the Maddrey DF is a liver-function number that often arrives alongside a metabolic-panel review, Acid Base Calculator helps interpret the bicarbonate and pH pattern that runs in parallel to the severity band.

Several things can move the score up or down, and a few of them are common in routine practice.

• • The discriminant function is a severity score, not a diagnostic test. A low score does not rule out alcoholic hepatitis, and a high score still needs a clinical exam, imaging, and the rest of the workup before treatment is decided.
• • The 32-point threshold was set in a 1978 steroid trial. Modern cohorts use MELD, ABIC, or the Lille score at day 7 to refine the steroid decision, so the DF result is best read alongside those tools rather than on its own.

Bleeding risk, kidney function, infection status, and nutrition matter for what to do with the result, but those are not part of the DF score. The calculator intentionally stops before that step so the result is a severity summary, not a treatment order.

The PT prolongation row in the result panel shows how much of the MDF score came from the coagulation panel, which is useful when vitamin K or FFP has been given.

According to STOPAH trial (Thursz et al., NEJM 2015), prednisolone's 28-day mortality reduction in severe alcoholic hepatitis did not reach statistical significance, with no improvement at 90 days or 1 year, and pentoxifylline did not improve survival over placebo, so the steroid decision stays a careful clinical judgment.