Fibrosis-4 (FIB-4) Index for Liver Fibrosis

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Results

Fibrosis-4 Score

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What is Fibrosis-4 (FIB-4)?

FIB-4 combines age and routine blood results as a noninvasive liver-fibrosis assessment aid.

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How to Use This Calculator

  1. Enter or select Age, AST, ALT, Platelet count.
  2. Check the unit beside each measurement. For a percentage or rate, use the scale and time period stated in the form.
  3. Choose Calculate, then compare the output with the formula and example below. If you change a value or option, calculate again to update the result.
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Formula Used

FIB-4 = age × AST/(platelets × √ALT), with platelets in 10⁹/L.
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Variables Explained

InputWhat it means
AgeAge in the time unit shown; most adult equations use completed years.
ASTAspartate aminotransferase concentration or activity from the laboratory report.
ALTAlanine aminotransferase activity, entered in the unit required by the equation.
Platelet countPlatelet concentration, using the scale specified by the equation or input label.
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Worked Example

Age 50, AST 40, ALT 40 and platelets 200 give FIB-4≈1.58.

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Why Use This Calculator?

Use the calculation to make the method and its inputs easier to check with a healthcare professional. Its meaning depends on the clinical setting and on whether the underlying method is appropriate for that person.

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Common Mistakes

    • Cutoffs depend on age and clinical setting; acute illness can alter the laboratory inputs.
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Frequently Asked Questions

Is this result a diagnosis or treatment instruction?

No. It describes a calculation or score from the supplied information. A qualified clinician must check the measurements, the method’s applicability and the wider clinical picture.

Can I enter the units from any lab report?

Use the units specified in the form and select a conversion only where the page provides one. Different substances need different conversion factors; a mismatch can produce a plausible but incorrect result.

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Sources & References