Biotin and Lab-Test Interference: Thyroid, Troponin and Other Tests
Biotin supplements can make some blood tests read falsely high or low, including troponin and thyroid tests. What the FDA page and published reports say, and why to tell the lab.
Content last updated . This page has not been medically reviewed.
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If you take biotin, or a hair, skin and nail product that contains it, tell the clinician and the lab before any blood test. The US Food and Drug Administration (FDA) says biotin, often found in dietary supplements, can significantly interfere with certain lab tests and cause incorrect results that may go undetected. [1] If you think you are having a heart attack, call 911 (US) and mention any biotin you take. Do not start, stop or change any prescribed medicine or vitamin on your own because of this page. This page is information only.What "interference" means
Some lab tests use biotin as part of how they work (a biotin and streptavidin link in an immunoassay). If a lot of biotin is already in the blood sample, the test can be thrown off. A review explains that biotin can falsely raise a result in one test design (competitive) and falsely lower it in another (sandwich). [2] So the same supplement can push one result up and another down. The error is in the measurement. It does not mean the body itself has changed.Which tests have been reported
| Test | What was reported | Strength of evidence |
|---|---|---|
| Troponin (a heart-attack marker) | The FDA says it continued to receive reports that biotin interference caused falsely low troponin results. It also lists troponin test devices that it says are subject to biotin interference but have not addressed the risk. [1] | Documented by a regulator (US) |
| Thyroid tests | A review describes falsely high free T4 and free T3 and a falsely low thyroid-stimulating hormone (TSH) with some assay designs. [2] | Documented in reviews |
| A case of apparent Graves disease | A man taking biotin megadoses had very high thyroid hormones and low TSH without symptoms. Stopping biotin resolved the abnormal results. [3] | Case report (one patient) |
| Other hormone and antibody tests | The same report says non-physiologic biotin intake may interfere with several immunoassays, including thyroglobulin and TSH receptor antibody tests. [3] | Case report |
The FDA's own safety communication (first issued in 2017 and later updated) is linked from its troponin page. The FDA page says that since 2017 some test makers have fixed the problem and others have not. [1] We could not open the safety communication itself this session, so we do not quote its recommendations here.
How common is it?
It depends on the person, the product and the test. A UK laboratory measured biotin in 524 leftover blood samples: all were below 10 micrograms per liter, and the authors judged interference extremely likely to be rare there, except for tests with the lowest thresholds, such as one troponin I assay. [4] The same paper reports that, in earlier work, 7.4% of US samples and 0.8% of Australian samples were at or above the 10 micrograms per liter level. [4] These are lab-sample counts from different places, not a rate for any one person.What the reports suggest doing
- Tell the lab and the clinician what you take, including multivitamins and beauty products. The thyroid case report says asking about biotin should be part of evaluating anyone having endocrine tests. [3]
- Ask before the test, not after. That report suggested that stopping biotin for at least two days before biotin-sensitive tests should be sufficient. [3] This was one patient on megadoses, so it is not a rule for everyone, and the right timing is for your clinician or lab to decide.
- If a result does not match how you feel, ask whether biotin could be a reason. A thyroid review says interference should be suspected when results and symptoms do not agree. [5]
Related pages
Biotin (vitamin B7), Biotin for hair, skin and nails: the evidence, Deficiency testing and its limits and Thyroid problems and fatigue.Frequently asked questions
Can biotin change my thyroid test?
Yes, with some test designs. Reviews and a case report describe falsely high thyroid hormone results and falsely low TSH. [2][3]
Can biotin hide a heart attack on a troponin test?
The FDA has received reports of falsely low troponin results caused by biotin and warns clinicians and labs about it. [1] Tell emergency staff what you take, and call 911 (US) for chest pain.
Do I need to stop biotin before a blood test?
Ask your clinician or the lab. One case report suggested at least two days off biotin for sensitive tests, but timing depends on the test and the amount taken. [3]
Is biotin in a normal multivitamin enough to cause this?
We did not find a source that sets a safe amount for every test. A UK sample study found interference unlikely in most people. [4] Mention every supplement anyway.
Does this mean biotin is unsafe?
No. This page is about test results, not toxicity. The NHS says 0.9 mg or less a day in supplements is unlikely to cause harm. [7]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
How to read the evidence labels
Labels used on this page: documented by a regulator, documented in case reports and reviews, mixed and Proper evidence not found.
Safety notes
Proper evidence not found: for an exact amount of biotin that is safe for every test, or for a single waiting time that fits every lab. We searched PubMed (biotin interference, troponin, thyroid, prevalence) and the FDA troponin page and found device-specific and case-level information only.
References
- US Food and Drug Administration. Biotin interference with troponin lab tests: assays subject to biotin interference. Content current as of 06/21/2022. Read 2026-10-23.
- Dasgupta A. Immunoassay design and biotin interference. Adv Clin Chem 2022;109:165-183.
- Barbesino G. Misdiagnosis of Graves' disease with apparent severe hyperthyroidism in a patient taking biotin megadoses. Thyroid 2016;26(6):860-863.
- Sanders A, et al. Biotin immunoassay interference: a UK-based prevalence study. Ann Clin Biochem 2021;58(1):66-69.
- Favresse J, et al. Interferences with thyroid function immunoassays: clinical implications and detection algorithm. Endocr Rev 2018;39(5):830-850.
- Health Canada. Dietary reference intakes tables: Reference values for vitamins. Page dated 2025-11-19. Read 2026-10-23 through a web-fetch tool.
- NHS (UK). Vitamins and minerals: B vitamins and folic acid. Page last reviewed 3 August 2020. Read 2026-10-23.