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  • Mary PreFontaine Heim RPh FAAFM

Biotin Interfering with Lab Testing

The FDA recently posted a safety communication regarding Biotin (B7) on their Medwatch platform. Patients who are ingesting high levels of biotin in dietary supplements can have clinically significant incorrect lab test results. Although the lab test cited in the alert was a cardiac value, previous articles have appeared in the New England Journal of Medicine (NEJM) detailing interference with thyroid levels. As early as January 2016, the Endocrine Society alerted its members that high doses of Biotin could interfere with a specific type of lab testing; immunoassays that incorporate biotin and streptavidin into their design. Biotin can cause both falsely elevated or low results, depending on the immune assay format. A table published in NEJM in October 2016 showed free T3, free T4, testosterone, estradiol, progesterone, DHEAs, Vitamin B12 reporting falsely high with biotin interference and PSA, LH and FSH reporting falsely low.

Biotin appears in many supplements such as multi-vitamins, B-complexes and Hair, Skin and Nail formulations. Physicians are also using high doses of Biotin to treat mitochondrial disorders and multiple sclerosis. Although Biotin has a short elimination half life of two hours, the FDA states available data is insufficient to support recommendations for safe testing in patients taking high levels of biotin, including the length of time for biotin clearance from the blood. Best practice would be discontinuing Biotin at least 7 days prior to testing and reporting the Biotin dosage and last dosage date to the lab.


C. Crew email alert

Trambas CM et al. More on biotin treatment mimicking Graves Disease. N Engl J Med. 2016;375:1698-1699.

Bitsch R et all. Studies on bioavailability of oral biotin doses for humans. Int J Vitam Nutr Res. 1989;59(1):65-71.

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