Vitamins and Their Effects on Blood Tests

Just about every doctor’s appointment starts with the same question: what medications do you take? Listing your medications may feel tedious, but MedStar St. Mary’s Hospital in Leonardtown is reminding residents that it’s important to give an up-to-date rundown every visit to determine how these drugs might interact with each other — and even how they might impact important blood tests.

In 2017, the Food & Drug Administration issued a safety alert about the water-soluble vitamin B7, or biotin, found in many multivitamins and supplements. Daily biotin intake recommendations range from 5 to 35 micrograms, depending on a person’s age, gender, and other factors including pregnancy. Biotin is also ingested naturally through common foods like sweet potatoes, mushrooms, eggs, and spinach.

“Many dietary supplements promoted for hair, skin, and nail benefits contain biotin levels up to 650 times the recommended daily intake of biotin,” stated the FDA last year. “Biotin in blood or other samples taken from patients who are ingesting high levels of biotin in dietary supplements can cause clinically significant incorrect lab test results.”

The FDA has noted an increase in the number of reported adverse events — including a death — related to interference with lab tests by biotin. Biotin in lab test results can cause falsely high or low results, depending on the type of test, and the influence of biotin might not always be obvious to health care providers or labs.

“Incorrect test results may lead to inappropriate patient management or misdiagnosis,” the FDA cautioned. “For example, a falsely low result for troponin, a clinically important biomarker to aid in the diagnosis of heart attacks, may lead to a missed diagnosis and potentially serious clinical implications.”

High levels of biotin can skew the results of common tests that are used to diagnose conditions like pregnancy, thyroid disease, cancer, anemia, heart disease, and other hormonal-related conditions. Fortunately, it usually only takes one day without taking the supplement to get accurate test results.

It’s important to keep an up-to-date list of all current medications on file with doctors so they are available for other medical providers. Be sure to note if you are currently taking a vitamin with biotin, and consider bringing labeled multivitamins to appointments so contents can be recorded.

Visit MedStar St. Mary’s laboratory website to learn more about laboratory services offered through MedStar St. Mary’s and prepare for your next blood test.

MedStar St. Mary’s Laboratory Centers

Belmont Building
23000 Moakley St.
Suite 205, Leonardtown

East Run Center
45870 East Run Drive
Lexington Park

MedStar St. Mary’s Hospital
25500 Point Lookout Road
Leonardtown

For more information and one-click access to a full list of resources available at MedStar St. Mary’s Hospital, visit its Leader member page.