What is the Fib-4 (Fibrosis-4) index threshold for FibroScan (Transient Elastography)?

From the Guidelines

The FIB-4 threshold for determining when to proceed with a FibroScan is typically considered to be 1.3, with scores below this value indicating low risk of advanced fibrosis and scores above 2.67 indicating high risk, as supported by the 2021 study published in Gastroenterology 1.

Key Points to Consider

• Patients with a FIB-4 score below 1.3 generally have a low risk of advanced fibrosis and may not require a FibroScan, as indicated by a negative predictive value of ≥90% 1.
• Those with scores above 2.67 are at high risk for advanced fibrosis, with positive predictive values of 60%–80%, and should be considered for referral to hepatology for further evaluation, including liver stiffness measurement (LSM) or liver biopsy 1.
• The indeterminate range of 1.3 to 2.67 may benefit from FibroScan evaluation to assess liver stiffness more directly, especially in patients with discordant or indeterminate LSM results, as recommended in the 2021 study published in Gastroenterology 1.

Clinical Application

• The FIB-4 score is a useful, inexpensive, first-line assessment of liver fibrosis for use in primary care, calculated using age, platelet count, AST, and ALT values 1.
• Clinicians should consider repeat testing with FIB-4 in 2–3 years for patients with initial scores below 1.3, as the prevalence of advanced fibrosis in primary care clinic populations is higher than previously believed, ranging from 9% to 15% in different studies 1.
• For patients with indeterminate FIB-4 scores, a simplified rounded value of 8.0 kPa on liver stiffness measurement (LSM) using vibration-controlled transient elastography (VCTE) can be used to exclude clinically significant fibrosis, with a sensitivity of 93% to exclude advanced fibrosis, as supported by the 2021 study published in Gastroenterology 1.

From the Research

Fib4 Threshold for Fibroscan

• The FIB-4 index is used to stratify patients at risk for metabolic dysfunction-associated steatotic liver disease (MASLD) as low-, indeterminate-, or high-risk for developing advanced liver fibrosis 2.
• Studies have shown that using FIB-4 in the AGA/AASLD guidelines to risk-stratify subjects at risk for MASLD-associated fibrosis results in many subjects being misclassified into the low- and high-risk categories 2.
• The novel cutoff points for the FIB4 index categorized by age increase the diagnostic accuracy in NAFLD, with proposed low and high cutoff points of 1.05 and 1.21 in ≤49 years, 1.24 and 1.96 in 50-59 years, 1.88 and 2.67 in 60-69 years, and 1.95 and 2.67 in ≥70 years 3.
• For liver cirrhosis diagnosis with FibroScan, the optimal cut-off values for the patients with HCC overall, left HCC and right HCC were 8.85,11.75 and 8.70 kPa, respectively 4.
• The optimal cut-off liver stiffness values for the diagnosis of varices were all 11.2 kPa, and the optimal cut-off values of FIB-4 and APRI for predicting varices were 2.64 and 0.71, respectively 4.
• The combination of a blood test and Fibroscan improves the non-invasive diagnosis of liver fibrosis, with the most accurate synchronous combination being FibroMeter+LSE, which provided a significantly higher area under the receiver operating characteristic curve than LSE alone or Fibrometer 5.

Key Findings

• FIB-4 index cutoff points for predicting advanced fibrosis in NAFLD increase with age 3.
• FibroScan, FIB-4, and APRI have moderate accuracy for liver fibrosis diagnosis and oesophageal varices prediction in patients with hepatoma 4.
• The synchronous combination of a blood test plus LSE improves the accuracy of the non-invasive diagnosis of liver fibrosis and decreases the biopsy requirement in the diagnostic algorithm 5.

Diagnostic Accuracy

• The diagnostic accuracy of FibroScan, FIB-4, and APRI for liver fibrosis diagnosis and oesophageal varices prediction in patients with hepatoma is moderate, with accuracy ranging from 64.3% to 78.4% 4.
• The combination of FibroMeter and LSE provides a significantly higher area under the receiver operating characteristic curve than LSE alone or Fibrometer, with a diagnostic accuracy of 91.9% 5.