Ingesting Biotin in Large Doses Can Interfere with Lab Tests, New UMN Study Shows

A preliminary study conducted by UMN Medical School researchers and published in the Journal of American Medical Association (JAMA) found the use of biotin supplements – also called vitamin B7 – can interfere with diagnostic tests.

“This is an emerging issue that the medical community needs to consider before they order lab tests or interpret results for patients taking biotin supplements,” said study author Danni Li, Ph.D., assistant professor in the department of laboratory medicine and pathology at the University of Minnesota Medical School. 

Lab tests for many conditions like hyperthyroidism, heart disease, and others rely on antibodies or analogs that exploit the binding between biotin and a protein called streptavidin to detect low analyte levels. They are called biotinylated immunoassays.

In recent years, more people have started supplementing their diets with biotin, commonly used for hair growth or management of diabetes. This study demonstrates that excessive biotin in a blood sample can compete with the biotinylated components used in diagnostic tests, rendering them inaccurate.

The researchers looked at 37 tests that measured 11 hormone and non-hormone analytes associated with various diseases among six healthy participants. Participants took 10 milligrams of biotin per day for seven days. Twenty-three of the tests included biotinylated components and 14 of them did not.

None of the non-biotinylated tests were affected. However, of the 23 biotinylated tests, nine showed falsely negative or falsely positive results. These clinically important discrepancies suggest physicians may want to ask about biotin ingestion before ordering lab tests or when interpreting results.

“We don’t need to scrap the use of biotinylated immunoassays because they are very good tools in many situations,” said co-author Angela Radulescu, M.D., assistant professor within the division of diabetes, endocrinology and metabolism at the University of Minnesota. “But we do need to consider potential biotin interference with lab tests for patients who take biotin supplements, especially in large doses like 10 milligrams per day. It may be advisable for patients to stop taking biotin before undergoing lab testing.”

A review of 376 lab tests that are used by clinical laboratories across the U.S. and the world showed 221 are biotinylated immunoassays.

While this JAMA study demonstrates ingestion of 10 milligrams of biotin per day for one week was associated with potentially clinically important assay interference in some of the biotinylated assays studied, the researchers hope to design a similar, larger-scale study. With additional data, they expect to learn more about the nuances of biotin supplement ingestion interference with biotinylated immunoassay lab tests. 

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