FIB-4 Calculator

Interpreting the FIB-4 score

Once you’ve entered your patient’s details, refer to the table below to interpret their FIB-4 score and guide the next steps in management.

Results chart

Management based on FIB-4 score

Once you’ve calculated your patient’s FIB-4 score, follow the recommended steps below to assess their risk of advanced liver fibrosis and determine appropriate management.

Low risk (FIB-4 <1.3) → routine monitoring

• Advanced fibrosis is unlikely, and ongoing monitoring in primary care is recommended.
• Patients with MAFLD and a low FIB-4 score (<1.3) should have their metabolic risk factors actively managed.
• Repeat non-invasive fibrosis testing in 3 years to reassess fibrosis risk.

Indeterminate risk (FIB-4 = 1.3–2.7) → further assessment required

• Patients with an indeterminate FIB-4 score (1.3–2.7) should undergo second-line assessment with:
  • Liver elastography (e.g., FibroScan®) or
  • A direct liver fibrosis serum test (e.g., ELF test or Hepascore).
• If these tests are unavailable, referral to a clinician with expertise in liver disease should be considered.
• If second-line testing indicates low risk of advanced fibrosis, repeat FIB-4 at least every 3 years.

High risk (FIB-4 >2.7) → specialist referral

• Refer patients for further evaluation if their FIB-4 score is greater than 2.7; there are elevated results of a direct liver fibrosis serum test or elastography; or there is clinical, laboratory or imaging evidence of cirrhosis. 
• Patients with cirrhosis who are willing and suitable for hepatocellular carcinoma (HCC) therapy should undergo surveillance for HCC every 6 months using appropriate imaging with or without serum AFP testing.

Monitoring considerations 

• For patients 75 years or older who have MAFLD, routine monitoring for fibrosis progression should be performed on a case-by-case basis, depending on their comorbid conditions and life expectancy.
• Weight, BMI and/or waist circumference should be monitored at least annually in patients with MAFLD to guide management.
• Patients with MAFLD should be monitored for the development of type 2 diabetes according to current Australian guidelines.

For more details on the evidence behind these recommendations, refer to the ‘Evidence’ tab.

Evidence supporting the use of FIB-4 in MAFLD assessment

FIB-4 Index is calculated using the following formula:

Background

• FIB-4 was originally developed to predict advanced fibrosis in patients with HIV/HCV coinfection.¹
• It is now used internationally as an accurate predictor of liver fibrosis, validated in multiple populations and ethnicities.²
• FIB-4 has been recommended for fibrosis assessment in MAFLD by several international guidelines, including the Gastroenterological Society of Australia’s (GESA’s) Metabolic dysfunction-associated fatty liver disease (MAFLD) consensus statement.^2-4
• Although liver biopsy remains the gold standard for assessing fibrosis in MAFLD, it is invasive and costly.
• Non-invasive tests such as FIB-4 are valuable screening tools to identify patients at higher risk of developing complications of liver disease, and can support decisions on further testing and specialist referrals. 

Utility of FIB-4 Based on the Gastroenterological Society of Australia (GESA) Metabolic Dysfunction-Associated Fatty Liver Disease (MAFLD) Consensus Statement²

• The risk of advanced liver fibrosis requires assessment using the non-invasive serum-based Fibrosis-4 (FIB-4) Index.
• A low FIB-4 score (<1.3) is associated with a >95% negative predictive value for advanced liver fibrosis.
• Patients with an indeterminate FIB-4 score (1.3–2.7) should undergo second-line assessment with liver elastography or a direct liver fibrosis serum test or, if these tests are unavailable, should be referred to a clinician with expertise in liver disease.
• Patients with MAFLD and a high FIB-4 score (>2.7), elevated results of a direct liver fibrosis serum test or elastography, or with clinical, laboratory, or imaging evidence of cirrhosis should be referred for further evaluation.
• Patients with MAFLD and a low FIB-4 score (<1.3) or low elastography or direct liver fibrosis serum test results should have their metabolic risk factors actively managed and be monitored with a repeat FIB-4 Index performed at least every 3 years.

Accuracy

• The accuracy of FIB-4 is highly dependent on age.
• FIB-4 is not reliable for use in patients younger than 35 years. These patients should receive alternative fibrosis assessment to ascertain fibrosis risk.
• For patients older than 65 years, a higher FIB-4 threshold of 2.0 should be used due to reduced specificity.
• For patients 75 years or older who have MAFLD, routine monitoring for fibrosis progression should be performed on a case-by-case basis, depending on their comorbid conditions and life expectancy.

Limitations of FIB-4 in clinical practice²

• Potential false positives:
  • Acute hepatitis
  • Immune thrombocytopenic purpura
  • Harmful alcohol use
• Cut-off values specific for MAFLD:
  • The upper and lower cut-off values of 1.3 and 2.67 are specific to MAFLD.
  • Different cut-off values should be used for chronic viral hepatitis.
• Indeterminate range:
  • Requires additional testing with liver elastography or a direct serum fibrosis test.
• Low positive predictive value (PPV) for advanced fibrosis:
  • Further tests are required to confirm the presence of advanced fibrosis.

References

1. Sterling RK, Lissen E, Clumeck N, Sola R, Correa MC, Montaner J, et al. Development of a simple noninvasive index to predict significant fibrosis in patients with HIV/HCV coinfection. Hepatology. 2006;43(6):1317-25.
2. MAFLD Consensus Statement Working Group. Recommendations for the assessment of metabolic dysfunction-associated fatty liver disease (MAFLD) in primary care: a consensus statement. Melbourne: Gastroenterological Society of Australia, 2024.
3. Berzigotti A, Tsochatzis E, Boursier J, Castera L, Cazzagon N, Friedrich-Rust M, et al. EASL Clinical Practice Guidelines on non-invasive tests for evaluation of liver disease severity and prognosis – 2021 update. Journal of Hepatology. 2021;75(3):659-89.
4. Kanwal F, Shubrook JH, Adams LA, Pfotenhauer K, Wai-Sun Wong V, Wright E, et al. Clinical Care Pathway for the Risk Stratification and Management of Patients With Nonalcoholic Fatty Liver Disease. Gastroenterology. 2021;161(5):1657-69.