A new case report in the Journal of the Endocrine Society documents how a patient's use of a biotin supplement, caused her to have clinically misleading test results, which prompted numerous consultations and unnecessary radiographic and laboratory testing. 

In November 2017, the U.S. Food & Drug Administration issued a warning "alerting the public, health care providers, lab personnel, and lab test developers that biotin can significantly interfere with certain lab tests and cause incorrect test results which may go undetected." 

The patient in the case report took a 5,000 mcg dose of biotin daily. Biotin supplements in that dosage are commonly sold over-the-counter, without a prescription, in many grocery and drug stores for about $8-$20 a bottle. They are marketed as being good for healthy hair, skin and nails.

In this patient's case, "The negative clinical impact included weeks of psychological distress concerning the possibilities of hypercortisolemia or a testosterone-producing tumor. Most significantly, these abnormal test results nearly resulted in an unnecessary invasive procedure for a complex patient with a hypercoagulable state," the case report says.

"The literature is lacking with regard to biotin interference with serum cortisol and testosterone immunoassays, as in our case-report," says Maya Styner, MD, associate professor of endocrinology and metabolism in the department of medicine and the case report's corresponding author. "Patients are ingesting supplements in a higher frequency, and higher doses, and therefore this case is timely and relevant from both a clinical and basic-science perspective."

She adds, "Our manuscript is a product of a collaboration between endocrinology, reproductive endocrinology/gynecology and clinical chemistry at UNC and at the Mayo Clinic. This collaboration enabled us to ascertain the underlying diagnosis and perform relevant research-based biotin quantification in our patient’s sample." 

Co-authors of the case report are Heather M. Stieglitz, PhD, Nichole Korpi-Steiner, PhD,  Brooke Katzman, PhD and Jennifer E. Mersereau, MD.  All are at UNC except for Katzman, who is co-director of the Hospital Clinical Laboratory and Point of Care, at the Mayo Clinic in Rochester, Minnesota.

PHOTO CREDIT: UNC School of Medicine

PHOTO CAPTION: This case report was led by Maya Styner, M.D., Associate Professor, University of North Carolina School of Medicine.