Biotin and False Test Results: Stopping Before Blood Tests is Essential

Stopping Before Blood Tests is Essential

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Many supplements contain biotin at levels well above the recommended daily intake of 30 micrograms. It is now recognized that high doses of biotin can interfere with some laboratory tests (specifically immunoassays using biotinylated antibodies). Many supplements contain 2 500, 5 000  or even 10 000 micrograms of biotin.

Both falsely low and falsely high results are possible in users of biotin supplements. The concern is that some patients might undergo unnecessary testing or start unnecessary medications after being told their blood test results are abnormal.

The issue is therefore potentially quite serious. In November 2017, the US Food and Drug Administration recently issued a safety communication regarding biotin interference with laboratory tests.

A recent report in the Journal of the Endocrine Society reported a patient with abnormal thyroid results, as well as elevated cortisol and testosterone. These abnormal results prompted the patient to undergo numerous consultations and radiographic and laboratory tests.

It was ultimately discovered in this patient that her abnormal results were due to the biotin supplement she was using. The patient was taking a biotin supplement at a dose of 5 000 micrograms per day regularly.  Once she stopped biotin, her lab parameters returned to normal although TSH tests (thyroid testing) did take more than 2 weeks before any normalization was seen.

This reports highlights the potential for patients using biotin to have false results. What is more concerning is the potential for such patients to undergo potentially invasive testing or start potentially harmful medications on account of these results.

Education as well as communication between health care teams, laboratories, and patients is vital to ensure patients stop biotin well ahead of any testing.


Stieglitz HM, et al. Suspected Testosterone-Producing Tumor in a Patient Taking Biotin Supplements.
J Endocr Soc. 2018.

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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