Strategies for mitigating risk posed by biotin interference on clinical immunoassays.

Recently, biotin use as an oral supplement has increased significantly among the general population. Biotin is a water soluble B-vitamin and is marketed to improve the cosmetic appearance of hair, skin, and nails. In addition, high-dose biotin (>5 mg/day) is prescribed to treat inborn errors of metabolism and multiple sclerosis. Many commercial immunoassays employ the high affinity interaction between biotin and streptavidin, a protein purified from bacteria, as part of the analyte capture mechanism. As such, these immunoassays are subject to this interference. The list of affected immunoassays is vendor specific but includes tests for troponin, serum and urine Beta hCG, thyroid function, and tumor markers. The interference can be positive or negative in nature depending on the immunoassay. To address this issue, patients are recommended to abstain from taking biotin supplements for 48 h, and laboratorians and clinicians must be familiar with the potential for biotin interference in performed lab tests. Here we describe strategies to treat high biotin specimens and make them suitable for testing; and detail a number of approaches used successfully by our laboratory to educate patients, doctors, and other healthcare professionals about this interference and to mitigate the posed patient safety risk.