How Biotin Induces Misleading Results in Thyroid Bioassays: Case Series

Abstract

Biotin is widely available over the counter in different doses and is used medically in the management of hair and nail problems. Recent literature suggested the use of high doses of biotin for the treatment of progressive multiple sclerosis. We present four cases that show a misleading increase in thyroid function tests toward a false diagnosis of Grave's disease after the administration of 20-30 mg biotin for different periods. All the four cases are free of the signs and symptoms of hyperthyroidism, and all of their results returned to baseline values within 24-48 hours after biotin withdrawal. The assemblage of these cases, thyroid assay results, and biotin doses had occurred by chance, with no selection bias, and they represented all cases of biotin interference with thyroid assays in our center during this year. The first case is a 23-year-old female who was diagnosed with Grave's disease during a routine checkup after she ingested a prescribed 20 mg biotin per day for three months for excessive hair fall. The second case is a 19-year-old female with hair and nail problems associated with iron deficiency anemia. She administered a self-prescribed biotin dose of 20 mg a day for a month. She asked an endocrinologist's opinion about a recent increase in her thyroid function tests, with no signs of hyperthyroidism. The third case is a 45-year-old man with near-total thyroidectomy for retrosternal multinodular goiter with compressive symptoms. His usual levothyroxine dose had been decreased from 100 to 50 microgram per day, after which he felt unwell and gained four kilograms, with signs and symptoms of hypothyroidism. His investigations were consistent with hyperthyroidism while his signs were of hypothyroidism, which was illogical. He was administered 30 mg medically prescribed biotin for nail changes due to recently diagnosed psoriasis. The fourth case is that of one of the authors who volunteered to take 30 mg of biotin daily for one week. His initial investigations were in the normal range but changed within this period to be Grave's disease-like, with no signs or symptoms. In conclusion, the ingestion of 20 mg or more of biotin may lead to a clinically relevant thyroid assay interference. The clinicians must take this point in consideration before assessing the results of any thyroid function tests.

Gut Microbiome Alterations in Patients With Thyroid Nodules

“…In addition, biotin (vitamin H) biosynthesis was positively associated with FT3 (Spearman’s correlation test, p < 0.05) but did not withstand age adjusting. Interestingly, biotin, which is commonly used, might induce abnormal thyroid function test results ( Ardabilygazir et al., 2018 ) via its direct effect on increasing thyroid hormone and reducing TSH concentrations ( Katzman et al., 2018 ; Odhaib et al., 2019 ).…”

Understanding and managing biotin interference in immunoassays

“…1d) [4,10]. In the presence of excess biotin, while a TSH test using biotin-streptavidin technology can produce falsely lower, falsely increased fT3 and/or fT4 results can obtain and hence it can mimic hyperthyroidism as presented by Kwok and colleagues' report as well as the others [14][15][16][17].…”

Abnormal thyroid test results in euthyroid state: An appraisal of the role of drugs

“…SBIS is widely used in many Food and Drug Administration approved immunoassay systems using fully automated platforms, including Access, DxI, and DxC (Beckman Coulter, California, US); the Elecsys, Cobas, and Modular platforms (Roche Diagnostics, Basel, Switzerland); the Isys platform (Immuno Diagnostic System, East Boldon, United Kingdom); the Ortho Vitros platform (Ortho Clinical Diagnostics, New Jersey, US); the Dimension Vista, Exl, Immulite platforms (Siemens Healthineers, Erlangen, Germany), Abbott Architect i2000® (Abbott Diagnostics, Illinois, United States), and Diasorin Liaison XL® (DiaSorin, Saluggia, Italy). 2 Type of abnormality: The presence of excess biotin in test samples causes abnormalities in accordance with the type of immunoassay. Falsely low readings occur with sandwich immunoassays (glycoprotein hormones like TSH) and falsely high values in competitive immunoassays (e.g.…”

“…triiodothyronine (T3), thyroxine (T4), steroid hormones and 25-hydroxy-vitamin D). 2 1. Mechanism of interference with sandwich immunoassays: When the assay has a "sandwich" design as employed for estimation of TSH, the test serum is incubated with biotinylated monoclonal TSH antibodies and radiolabelled monoclonal antibodies.…”

“…Though the effect of biotin on FT3, FT4 and TSH estimation wanes in hours, anti-TSH receptor antibodies (TRAbs), which can also be falsely elevated due to this assay interference, may take up to 7 days to normalise. 2,[8][9][10] Clinical correlate: The TFT could falsely suggest a diagnosis of overt or subclinical thyrotoxicosis or thyroid hormone resistance, and falsely elevated TRAbs can further mislead the diagnosis. History of intake of OTC vitamin supplements containing biotin should be elicited.…”