Question 1

Why do the thresholds differ for patients aged ≥ 65?

Accepted Answer

Age is a component of the FIB-4 formula, so older patients have higher FIB-4 values even without fibrosis. To maintain specificity in older adults, the low-threshold rule-out cut-off is raised to < 2.0 and the high-threshold rule-in cut-off to > 3.5. These age-adapted thresholds improve diagnostic performance in elderly populations.

Question 2

Can FIB-4 be used in patients with normal LFTs?

Accepted Answer

Yes — in fact, FIB-4 is often most useful in patients with only mildly elevated or even normal transaminases, particularly in NAFLD where significant fibrosis can be present despite normal ALT. This is the scenario where FIB-4 screening is most impactful.

Question 3

Does FIB-4 work in acute hepatitis?

Accepted Answer

No — FIB-4 was designed for chronic liver disease. In acute hepatitis, ALT and AST can be massively elevated from acute hepatocellular injury, producing severe ALT/AST ratio distortions that make FIB-4 unreliable. Defer fibrosis assessment until the acute episode resolves.

Question 4

What if FIB-4 and APRI disagree?

Accepted Answer

Discordance between non-invasive tests occurs in approximately 20–30% of patients. EASL guidelines recommend proceeding to a second-line test (FibroScan, ELF, or MRE) when the two scores disagree. The patient is considered indeterminate and should not be confidently classified as low or high risk based on serum biomarkers alone.