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Modified Maddrey Arithmetic Score

Evaluate the modified Maddrey expression from prothrombin times and total bilirubin.

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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Use the result with context

Health results are educational estimates, not a diagnosis or treatment recommendation. A qualified clinician can interpret measurements in the context of your health.

Formula and method

Patient PT 20 seconds, control PT 12 seconds and bilirubin 5 mg/dL give a modified Maddrey score of 41.8.

Score = 4.6 × (patient PT − control PT) + bilirubin (mg/dL).

Worked example

Enter these known values and leave the other values blank.

Prothrombin time
20 sec
Prothrombin time - control
12 sec
Bilirubin level
5 mg/dL
Score
41.8

Assumptions and limitations

  • Patient and laboratory control PT are in seconds; total bilirubin is in mg/dL. The default control PT 12 seconds must be replaced with the laboratory control. This historical score does not determine treatment or prognosis by itself.
  • Use the displayed units and measurements from the same context. Editable fields support arithmetic inverses when enough independent values are supplied. Clear a preset value before solving it as an unknown.
  • This tool performs the stated arithmetic model. It does not establish a diagnosis, prescribe treatment or replace laboratory and clinical assessment.

Common questions

What does this calculation represent?

Patient and laboratory control PT are in seconds; total bilirubin is in mg/dL. The default control PT 12 seconds must be replaced with the laboratory control. This historical score does not determine treatment or prognosis by itself.

Can I solve for a different field?

Clear the unknown field and enter enough independent values in the remaining editable controls. A relationship cannot recover a unique value when a dividing quantity is zero.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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