In late November 2017, the FDA issued a warning that patients with elevated levels of biotin (vitamin B7) can experience incorrect laboratory results using certain immunoassays that rely on biotin technology.
Biotin is an over the counter vitamin supplement used for its purported effects in strengthening skin, hair and nails. It also is administered to some patients suffering from multiple sclerosis.
A typical biotin supplement contains 5000 – 10000 micrograms of biotin and these high dosages can cause interference with immunoassays relying on biotin containing reagents. Because there are two different types of biotin containing reagents used in immunoassays, in some instances, the results are incorrectly elevated while in other cases, results are incorrectly low, depending on the methodology used.
On November 6, 2019, FDA again issued a warning and specifically targeted troponin assays, which can be falsely low in patients with highly elevated biotin concentrations in their blood. This is a troublesome situation, particularly treating patients in an emergency room presenting with symptoms of potential myocardial infarction. The FDA indicated that some assay manufacturers had successfully mitigated the biotin interference of their assays, but others had not yet addressed the issue.
The FDA presented several recommendations for consumers, health care providers and laboratory personnel.
For consumers, recommendations include:
- Patients should notify their providers if they are currently consuming any biotin supplements.
- Be aware biotin can be found in multivitamins where the biotin dosage can vary significantly. The high dose supplements containing biotin alone will have the highest concentrations of biotin. Patients need to keep in mind that the daily-recommended allowance for biotin is 0.03 mg/day.
- If a laboratory test has been performed and a patient is concerned about the result, the patient should address their concern about potential biotin interference to their provider.
- A health sheet explaining biotin for consumers is available at https://ods.od.nih.gov/factsheets/Biotin-Consumer/.
For providers recommendations include:
- Be aware biotin supplements can interfere with laboratory tests performed by immunoassay. These include diagnostic cardiovascular and hormone assays that may be subject to interference if the dosage is elevated in a specimen.
- Alert patients about effects of biotin supplements or multivitamin supplements that may contain biotin. If the supplement is high dosage for hair, skin and nails, more than likely it will have a high biotin level. Provide patients with the above web site so they can become more knowledgeable.
- Include on the requisition for the laboratory test if the patient is consuming a biotin supplement.
- Help educate fellow practitioners about biotin interference when biotin is administered in higher than recommended daily allowances.
- The timeframe for the biotin to clear the blood is unknown.
- Communicate with the laboratory if you have questions about biotin technology and for information concerning use of biotin reagents in testing you are ordering.
- Remain acutely aware that there are certain troponin assays where the risk of biotin interference has not yet been addressed. Communicate with your testing laboratory to determine if they are utilizing testing methodologies where this can be a problem. I see it as keenly important for emergency room and urgent care practitioners to know if the troponin and other cardiac studies they are ordering on biotin consuming patients are being tested by a methodology wherein biotin can cause incorrectly low levels of troponin.
For laboratorians the recommendations include:
- Be aware if your immunoassay assays utilize biotin technology. Remember it is not possible to identify specimens with increased biotin.
- Alert your clinicians if biotin will interfere with immunoassays, especially alert emergency and urgent care facilities of effect on troponin and other cardiac assays where the result of testing may be falsely low.
- When collecting specimens in the laboratory question patients if they are consuming biotin supplements, especially those containing high dose biotin.
- Remember, there is not sufficient data about the length of time needed for biotin to clear from the blood.
- Question your reagent vendors about biotin interference with their testing methodologies.
The FDA has also published a listing of those manufacturers whose assays are subject to biotin interference. This is located at https://www.fda.gov/medical-devices/vitro-diagnostics/biotin-interference-troponin-lab-tests-assays-subject-biotin-interference
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