Biotin (vitamin B7) is found in many supplements, including multivitamins and prenatal vitamins, but particularly supplements that are labeled for their benefits to skin, hair, and nail growth.
The daily recommended limit for biotin is 0.03 mg, but many products contain 20 mg of biotin, and some products contain up to 100 mg of biotin per pill and the label recommends taking multiple pills per day.
The FDA is specifically concerned that biotin supplements can cause a falsely low result for troponin, a clinically important biomarker to aid in the diagnosis of heart attacks.
Hormone tests and cardiovascular diagnostic tests are potentially affected by biotin interference, according to the FDA. Incorrect test results may be generated if there is biotin in the patient’s sample, which can lead to a life-threatening misdiagnosis.
The FDA has received many adverse event reports, including one death due to a heart attack, related to biotin interference with lab test results.
Since the FDA first warned about the problem in 2017, some lab test developers have successfully minimized the problem by redesigning their tests — but others have not. The FDA has published a list of lab tests (called troponin assays) that have not yet addressed the risk.
Source: UPDATE: The FDA Warns that Biotin May Interfere with Lab Tests: FDA Safety Communication