Stopping Biotin before Blood tests: Important & maybe life saving

STOP Biotin Before Getting Blood tests

I'll mention today an important point that could be life saving for some patients - and that is that biotin supplements must be stopped at least 48 hours before and blood test to avoid false positive and false negative results.

Several papers have now convincingly demonstrated that biotin interferes with certain assays. Many assays rely on biotin-streptavidin that are part of the assay itself. Extra biotin from the patient's blood can really affect results of these tests. Some assays are affected differently than others, and the exact way that biotin can interfere can differ.

But the key point is that taking biotin supplements can interfere with assays for TSH, T3 and T4, B12 and parathyroid hormones.


Biotin can interfere with results of many assays and must be stopped 2 full days before any blood test. Failure to do so could lead to false results and trigger the clinician to order unnecessary (and potentially harmful) medications.


1) Biotin interference on TSH and free thyroid hormone measurement.
Kwok JS, et al. Pathology. 2012.

2) Misdiagnosis of Graves' Disease with Apparent Severe Hyperthyroidism in a Patient Taking Biotin Megadoses.
Barbesino G. Thyroid. 2016.

3) Biotin-Related Interference in TSH, T4 and B12 Immunoassays
Program: Abstracts - Orals, Poster Previews, and Posters
Session: FRI 265-319-Thyroid Case Reports I (posters)

Dr. Jeff Donovan is a Canadian and US board certified dermatologist specializing exclusively in hair loss. To schedule a consultation, please call the Whistler office at 604.283.1887

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