Biotin interference in immunoassays: recommendations of the SIBioC Working Group on Extra-AnalyticalVariability (WG-VEA).

Biotin is a water-soluble vitamin, which participates to a vast array of metabolic pathwaysinvolving fatty acids, carbohydrates and amino acids metabolism. This vitamin is also capable to form high-affinitybonds with various molecules, including streptavidin and avidin, which are essential components of manyimmunoassays based on the principle of biotin-streptavidin or biotin-avidin binding. In patients assuming high dosesof biotin, therefore, some competitive and non-competitive immunoassays may exhibit falsely increased and falselydecreased test results, respectively, with magnitude of interference depending on biotin concentration in the testsample and on specific vulnerability of the immunoassay. With the aim to provide some expert guidance foridentifying, preventing and managing biotin interference in clinical laboratory practice, this document contains a seriesof consensus recommendations endorsed by the Working Group on Extra-Analytical Variability of the Italian Societyof Clinical Chemistry and Clinical Molecular Biology (SIBioC). Briefly, the most important recommendationsencompass local evaluation of possible biotin interference, routine history taking on biotin intake for both inpatientsand outpatients, informing clinicians on potentially biotin-sensitive immunoassays, sample retesting 24-48 hours afterthe last biotin administration, along with possible consideration to add a note in the laboratory report highlighting themethods more vulnerable to biotin interference. Routine biotin measurement in all samples is currently discouraged.