The FIB-4 (Fibrosis-4 score) is a biomarker of the risk of severe fibrosis (ie F3 or F4 fibrosis). The FIB-4 is based on a simple algorithm that is calculated using the patient's age, platelet count, and transaminases.
The Fibrosis-4, or FIB4 score can correctly identify patients with severe fibrosis (F3-F4). A FIB4 ≤ 1.45 has a negative predictive value of 93.7% and a FIB4 > 4 has a positive predictive value of 66%. References: Formula: Fib4 = (Age x AST) / (Platelets x √[ALT]).