RESUMO
OBJECTIVE: Interleukin -6 (IL-6) is an important diagnostic test in COVID-19 patients to determine whether to initiate tocilizumab therapy or mechanical ventilation. We investigated potential interference of biotin in Roche IL-6 assay which utilizes biotinylated antibody. METHODS: We prepared three serum pools from left-over specimens which showed IL-6 values over 40 pg/mL. Then aliquots of each serum pool were further supplemented with various amounts of biotin expected in patients taking biotin supplement and then IL-6 values were measured again using Roche IL-6 assay on the Cobas e411 analyzer. RESULTS: We observed negative interference of biotin in IL-6 assay but interference was bimodal as maximum negative interference was observed with 100 ng/mL biotin but not with 1000 ng/mL. However, no interference was observed in the presence of 25 ng/mL biotin. CONCLUSIONS: Biotin showed negative interference with IL-6 assay.
