Interference From High-Dose Biotin Intake in Immunoassays for Potentially Time-Critical Analytes by Roche.

CONTEXT.—: Immunoassays using the interaction between streptavidin and biotin are used for clinical chemical analytes on platforms by many different manufacturers. The design can be susceptible to interference from high-dose biotin intake in patients, which remains an often-overlooked confounder despite recently increased awareness.

OBJECTIVE.—: To evaluate an easily implementable method of in vitro biotin depletion for the removal of biotin interference in immunoassays for potentially time-critical analytes.

DESIGN.—: A biotin stock solution was made and de-identified patient samples were spiked to reach a biotin concentration of 1.126 × 106 pg/mL, the maximum reported biotin concentration 1 to 2 hours after a single oral dose of 300 mg biotin. Then, the resulting interference in Elecsys immunoassays for cortisol, cyclosporine A, tacrolimus, digitoxin, thyroid-stimulating hormone, free triiodothyronine, free thyroxine, C-peptide, insulin, N-terminal pro-B-type natriuretic peptide, troponin T high sensitive, human immunodeficiency virus, procalcitonin, β human chorionic gonadotropin, toxoplasma immunoglobulin M, and toxoplasma immunoglobulin G was evaluated before and after biotin depletion using streptavidin particles.

RESULTS.—: All tested immunoassays, with the exception of toxoplasma immunoglobulin M and toxoplasma immunoglobulin G, suffered from significant biotin interference. The depletion protocol removed assay interference due to biotin and produced results that were close or identical to initial prespike measurements.

CONCLUSIONS.—: Despite an increase in turnaround times, biotin adsorption is a feasible countermeasure for biotin interference in Elecsys immunoassays. Until test kits with an increased resistance to the interference from high-dose biotin intake are distributed, the evaluated protocol can provide results properly reflecting the patient's clinical condition.