Fib-4: analytical and biological issues

Fib-4 is a simple calculation based on the patient’s age and measurements of platelets, AST ALT. It recommended in some clinical guidelines to assist with evaluation risk hepatic fibrosis. As any laboratory result, understanding analytical biological variation components required. Using median within-laboratory precision data (CVa) from RCPAQAP estimated CVa for FIB-4 result 5.7%. Liquid Serum Chemistry program total whole country (within between laboratory) approximately 10%. The within subject (CVi) was CVi input tests using EFLM database, giving 14%. Estimation gave 13%. To these sources must be added other factors such as possible pyridoxine depletion, where susceptible assays are used, interfering conditions (e.g., acute hepatitis, muscle damage, thrombocytopaenia causes). These findings suggest that decisions should not single estimation, patients optimally tested at one laboratory/with method when serial measurements. Laboratories could by supplying informative interpretative comments.