RT Journal Article
SR Electronic
T1 When thyroid labs do not add up, physicians should ask patients about biotin supplements
JF BMJ Case Reports
JO BMJ Case Reports
FD BMJ Publishing Group Ltd
SP e231337
DO 10.1136/bcr-2019-231337
VO 13
IS 3
A1 Michael S Lundin
A1 Ahmad Alratroot
A1 Fawzi Abu Rous
A1 Saleh Aldasouqi
YR 2020
UL http://casereports.bmj.com/content/13/3/e231337.abstract
AB A 69-year-old woman with a remote history of Graves’ disease treated with radioactive iodine ablation, who was maintained on a stable dose of levothyroxine for 15 years, presented with abnormal and fluctuating thyroid function tests which were confusing. After extensive evaluation, no diagnosis could be made, and it became difficult to optimise the levothyroxine dose, until we became aware of the recently recognised biotin-induced lab interference. It was then noticed that her medication list included biotin 10 mg two times per day. After holding the biotin and repeating the thyroid function tests, the labs made more sense, and the patient was easily made euthyroid with appropriate dose adjustment. We also investigated our own laboratory, and identified the thyroid labs that are performed with biotin-containing assays and developed strategies to increase the awareness about this lab artefact in our clinics.