Liver Fibrosis Score (FIB-4) Calculator
Calculate the FIB-4 index for non-invasive liver fibrosis assessment using age, AST, ALT, and platelet count. Includes APRI score and NAFLD-specific cutoffs.
Medical Disclaimer
This calculator is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about your health. Never disregard professional medical advice or delay seeking it because of results from this tool.
Inputs
Results
FIB-4 Index
1.37
Risk Category (0–2)
0
How to Use This Calculator
- Enter the patient's Age in years, AST in U/L, and ALT in U/L from current laboratory results.
- Enter Platelet Count in ×10⁹/L to complete the FIB-4 formula.
- Review the FIB-4 Index — values below 1.30 suggest low fibrosis risk, above 2.67 suggests advanced fibrosis.
- Check the APRI Score and AST/ALT Ratio (De Ritis) for additional non-invasive fibrosis markers.
- Use the risk category to guide decisions about liver biopsy or specialist referral.
How the result changes with Age (years)
| Age (years) | FIB-4 Index | Risk Category (0–2) |
|---|---|---|
| 26 | 0.71 | 0 |
| 47 | 1.29 | 0 |
| 71 | 1.94 | 1 |
| 92 | 2.52 | 1 |
What each input means
- Age (years)
- Patient age in years. FIB-4 is validated for adults 35–65 years.
- AST (U/L)
- Aspartate aminotransferase (SGOT) in units per liter.
- ALT (U/L)
- Alanine aminotransferase (SGPT) in units per liter.
- Platelet Count (×10⁹/L)
- Platelet count in 10⁹/L (e.g., 200 = 200,000/μL).
What each result means
- FIB-4 Index
- FIB-4 score. <1.45 = low risk, 1.45–3.25 = indeterminate, >3.25 = high risk.
- Risk Category (0–2)
- 0 = low risk (F0–F1), 1 = indeterminate (need further testing), 2 = high risk (F3–F4).
- NAFLD Risk (0–2)
- NAFLD-specific cutoffs: 0 = low (<1.30), 1 = indeterminate (1.30–2.67), 2 = high (>2.67).
- AST/ALT Ratio (De Ritis)
- De Ritis ratio. >1.0 may suggest cirrhosis or alcoholic liver disease.
- APRI Score
- AST to Platelet Ratio Index. <0.5 = low risk, 0.5–1.5 = indeterminate, >1.5 = high risk.
- APRI Risk (0–2)
- APRI-based fibrosis risk: 0 = low, 1 = indeterminate, 2 = high.
- Next Step (0–2)
- 0 = routine monitoring, 1 = consider elastography/further testing, 2 = elastography + hepatology referral.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersAge (years) = 50, AST (U/L) = 30, ALT (U/L) = 30, Platelet Count (×10⁹/L) = 200 = 4 input(s) provided
- Calculate FIB-4 IndexFIB-4 Index = round(fib4 * 100) / 1001.37 = 1.37
- Calculate Risk Category0 = 0
- Calculate NAFLD Risk1 = 1
- Calculate AST/ALT RatioAST/ALT Ratio1 = 1
Related Calculators
The questions that sit next to this one — chosen by subject, including calculators filed under a different category.
Child-Pugh Score Calculator
Classify severity of chronic liver disease and cirrhosis using five clinical parameters. Determines Child-Pugh class A, B, or C with survival estimates.
GastroenterologyMELD-Na Score Calculator
Calculate Model for End-Stage Liver Disease with Sodium correction for liver transplant prioritization.
GastroenterologyGERD Severity Score Calculator
Score gastroesophageal reflux disease severity using the GERD-Q questionnaire. Evaluates symptom frequency, daily-life impact, and suggests treatment approach.
More in Medical & Clinical.