Nikola Baumann, Ph.D., on Biotin and Laboratory Tests
At the 2018 American Association for Clinical Chemistry annual meeting in Chicago, Nikola Baumann, Ph.D., presented about how biotin can sometimes interfere with laboratory measurements. According to Dr. Baumann, it is essential for clinical laboratorians to know not only how assays in their lab work, but also how to explain potential interferences to clinicians.
Biotin supplements (also known as vitamin B7) have been promoted for thickening hair, strengthening nails, and improving skin, leading to an increase in their use. However, biotin supplement use has also led to an increase in reported cases of biotin interferences, increasing the potential for misdiagnoses.
Based on a survey of nearly 200 patients, Dr. Baumann and her colleagues discovered that only 8% of outpatients were aware that they were taking biotin supplements. Biotin interference can affect an extensive range of assays. These include assays used to diagnose and monitor malignancies (Tg, calcitonin, gastrin), thyroid disorders (TSH, free T4, total T4, free T3, total T3), bone and calcium homeostasis (PTH, 25-OH vitamin D), reproductive hormones (progesterone, LH, FSH, estradiol, DHEA-S, testosterone, beta-hCG), anemia (ferritin), and cardiac markers (NT-pro-BNP, troponin).
According to Dr. Baumann, biotin interference can happen because most immunoassay manufacturers rely on biotin-streptavidin capture in their assays. Biotin interference can cause a falsely increased result in competitive assays and a falsely low result in sandwich assays. A complicating factor is that the concentration of biotin that causes interferences is assay-dependent.
To identify biotin interference, Dr. Baumann suggested that laboratories can perform serial dilution checks to see if they are linear. Lab staff can also test the sample on a platform that does not use biotin-streptavidin capture.