Does biotin interfere with labs?

The U.S. Food and Drug Administration issued a safety communication in 2017 that biotin (vitamin B7) can interfere with laboratory tests that use biotin–streptavidin immunoassay technology. In 2019 the FDA updated that communication, still particularly concerned about falsely low cardiac troponin — a miss that can delay a heart-attack workup — and noted that some assay makers had mitigated interference while others had not. Falsely distorted TSH or free T4 matters for hair because thyroid disease sits on the American Academy of Dermatology’s shedding differential. Hair, skin, and nail supplements often contain biotin far above food-level intake. This is assay interference, not a demonstration that extra biotin grows androgenetic hair.

The AAD has long been skeptical of biotin for ordinary pattern loss in people who are not deficient. Stopping biotin before labs is a timing question for the ordering clinician and the lab’s method. The FDA has said there is not enough information to promise that holding biotin for a fixed number of hours prevents every wrong result — so do not invent a “stop 24 hours” protocol from a forum, and do not assume a mega-gummy is harmless because you feel fine. In an emergency department with chest pain, disclose biotin immediately; do not wait for a hair consult. This is not medical advice.

Other capsules in the same “hair formula” (high-dose vitamin C, B-complex that still contains biotin) belong on the list you hand the phlebotomist. If a thyroid or troponin number and your symptoms disagree, ask whether the method is biotin-sensitive rather than starting a second hair vitamin. Related HairBase pages cover biotin-as-growth-claim separately; this Q&A is the lab warning.

Fontes: AGA review (CCID) ↗

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