immunoassay
3 interactions related to immunoassay
levothyroxine + biotin
Biotin (vitamin B7) does not interact with levothyroxine pharmacologically and does not change how the medication is absorbed or works. The issue is in the lab: high-dose biotin can interfere with the biotin-streptavidin immunoassays used to measure TSH, free T4, free T3, and thyroglobulin, which can produce a falsely low TSH and falsely high T4/T3 pattern that mimics an overactive thyroid and can prompt an inappropriate dose change.
biotin + troponin test
High-dose biotin (vitamin B7) can interfere with the biotin-streptavidin chemistry used in many cardiac troponin immunoassays, potentially producing a falsely low result. The FDA has warned about this since 2017, but real-world data suggest clinically meaningful interference is uncommon at the doses found in typical over-the-counter supplements. The practical risk is real but narrower than once feared.
biotin + thyroid stimulating hormone test
High-dose biotin can interfere with the biotin-streptavidin immunoassays many labs use to measure TSH, free T4, free T3, and thyroglobulin. The result is a falsely low TSH alongside falsely elevated free thyroid hormones, a pattern that can mimic Graves' disease. Published case reports describe patients who were wrongly diagnosed with hyperthyroidism, and started on antithyroid drugs, because of biotin interference that resolved once biotin was stopped.