FDA Watch: Labs Warned that Biotin Interferes with Test Accuracy

In late November, the FDA issued a safety communication warning that the supplement biotin (Vitamin B7) may interfere with lab testing results.

Biotin Concerns…
Over-the-counter (OTC) use of biotin supplements has steadily increased. These products, which purportedly strengthen hair, skin, and nails, range in biotin dosage from 50 μg in multivitamin to as high as 10 mg in some biotin- only products. The FDA notes these high-dose OTC products may contain biotin levels up to 650 times the recommended daily intake of biotin (30 μg/day). Additionally, physicians recommend extremely high doses for treatment of neuropathy and multiple sclerosis.

The FDA biotin warning comes on the heels of a Roche study demonstrating that an eight-hour wait time or washout period is necessary for accurate test results when using streptavidin– biotin immunoassays following high doses, over 5 mg/day, of biotin. There have also been a number of case reports of biotin interference leading to incorrect diagnoses in both adults and children, particularly for cardiovascular and hormone tests.

High-sensitivity immunoassays made by companies like Abbott, Beckman Coulter, Ortho Clinical Diagnostics, Roche and Siemens Healthcare Diagnostics are all susceptible to biotin interference. Excess biotin in patient samples can result in falsely high test results with competitive assay design and falsely low results with sandwich assay design. A study in the International Journal of Pharmacokinetics found that manufacturers provide a "spectrum of guidance" in package inserts ranging from no mention or vague generic warnings of biotin interference to comprehensive specification on serum biotin concentrations.

…And What Labs Can Do to Address Them
To minimize the risk of biotin interference with lab tests and the adverse consequences they can produce, the FDA is recommending that lab personnel:

• Be aware that biotin levels above the recommended daily allowance may cause significant interference with particular lab tests;

• Talk to physicians and patients about use of assays with biotin technology;

• At draw centers, specifically ask patients if they are taking biotin;

• Educate health care providers about biotin interference with specific tests;

• Talk directly with the test manufacturer if they have any questions or concerns about potential biotin interference with a particular test.