As our patient's medication list become longer and longer with supplements, let's take a moment to talk about biotin.
The B vitamin that is marketed to improve hair and nail health can make a mess of your endocrinology labs. Dr. Hayward brought this up at her noon report on Monday on oligomenorrhea and this was discussed in the last year at our DOM Grand Rounds.
What's so confusing about biotin and how it affects your labs, is it can cause both positive and negative interference on assays. It can also cause false positive for TPO antibodies despite a patient having no phenotypic evidence of Grave's disease.
When in doubt, talk with the lab and/or endocrinology to help with testing. Endocrinology recommends holding biotin for at least 4 weeks before retesting.