Calculators/Hepatology & Gastroenterology/Non-Invasive Liver Fibrosis Suite (FIB-4, APRI, De Ritis Ratio)
Hepatology & GastroenterologyEvidence-Based Golden Standard
Non-Invasive Liver Fibrosis Suite (FIB-4, APRI, De Ritis Ratio)
Comprehensive non-invasive liver risk stratification combining FIB-4 index, APRI score, and De Ritis (AST/ALT) ratio for non-alcoholic fatty liver disease (MASLD/MASH) and viral hepatitis.
De Ritis = AST / ALT
FIB-4 = (Age × AST) / (Platelets × √ALT)
APRI = [(AST / AST_ULN) / Platelets] × 100
Published Clinical Benchmark Cases
Clinical Parameters & Inputs
Unit: U/L
U/L
Unit: U/L
U/L
Unit: ×10³/µL
×10³/µL
Enter value as integer (e.g. 180 for 180,000 /µL or 180 × 10⁹/L).
Unit: U/L
U/L
Standard textbook default is 40 U/L.
Computed OutputHigh Risk for Advanced Fibrosis / Cirrhosis (F3-F4)
2.8FIB-4 Score
Diagnostic Interpretation
FIB-4 is 2.8 (> 2.67). High positive predictive value for advanced fibrosis or cirrhosis. Urgent hepatology referral recommended for vibration-controlled transient elastography (FibroScan) or liver biopsy. Screen for portal hypertension and hepatocellular carcinoma. De Ritis > 1.0 in chronic hepatitis suggests progression toward advanced fibrosis or cirrhosis.
Calculation Breakdown
FIB-4 Index Calculation
(52 × 65) / (180 × √45) = 3380 / (180 × 6.71) =2.8
APRI Score Calculation
[(65 / 40) / 180] × 100 =0.9
De Ritis Ratio (AST/ALT)
65 / 45 =1.44 (De Ritis > 1.0 in chronic hepatitis suggests progression toward advanced fibrosis or cirrhosis.)
Clinical Decision Pearls
- AASLD and EASL clinical guidelines recommend FIB-4 as the primary first-line triage biomarker in primary care for all patients with metabolic risk factors (diabetes, obesity, MASLD).
- In patients ≥ 65 years old, physiological aging elevates FIB-4; use the validated adjusted low-risk threshold of 2.0 to avoid false-positive referrals.
- APRI > 1.5 has high specificity for cirrhosis in chronic hepatitis C and B.
Limitations & Confounders
- Acute transaminitis (acute hepatitis flare, rhabdomyolysis, strenuous exercise, hemolysis) falsely elevates FIB-4 and APRI by orders of magnitude.
- Not validated in patients under 35 years old.
Evidence & Citations
- Sterling RK, et al. Development of a simple noninvasive index to predict significant fibrosis in patients with HIV/HCV coinfection. Hepatology. 2006;43(6):1317-1325.
- Wai CT, et al. A simple noninvasive index can predict both significant fibrosis and cirrhosis in patients with chronic hepatitis C. Hepatology. 2003;38(2):518-526.
- Rinella ME, et al. AASLD Practice Guidance on the clinical assessment and management of nonalcoholic fatty liver disease. Hepatology. 2023;77(5):1797-1835.