FIB-4 Index Calculator

What is the FIB-4 Index?

The FIB-4 (Fibrosis-4) Index is a simple, non-invasive scoring system that uses a patient's age and three standard blood tests (AST, ALT, and platelet count) to estimate the severity of liver fibrosis.

It is widely used to screen for advanced fibrosis in patients with chronic liver diseases, such as Hepatitis C and Non-alcoholic Fatty Liver Disease (NAFLD), helping to identify patients who may require further investigation like a liver biopsy.

Why is it a Valuable Screening Tool?

• Excellent at ruling out advanced fibrosis, with a high negative predictive value (NPV).
• Reduces the need for invasive liver biopsies in low-risk individuals.
• Easy to calculate using readily available and inexpensive laboratory results.

Interpreting the Result (Common Cutoffs)

Clinical Pathway and Management

The FIB-4 score helps stratify patients into risk categories to guide clinical management. It is a powerful tool but should be used as part of a broader clinical assessment.

• Low Risk (<1.3): Indicates a low probability of advanced fibrosis. Routine follow-up is often sufficient.
• Intermediate Risk (1.3 - 2.67): The risk is indeterminate. Further evaluation with other non-invasive tests (e.g., FibroScan®) or consultation is recommended.
• High Risk (>2.67): Suggests a high probability of advanced fibrosis. Referral to a specialist for further workup is strongly advised.