Abstract
We report a case of a 52-year-old man who was referred by his primary care physician to rule out thyroid illness. His thyroid function tests (TFTs) revealed isolated elevation of total T3 (TT3) with normal total T4 (TT4), free T3 (FT3), free T4 (FT4), and unsuppressed thyroid stimulating hormone (TSH) raising the suspicion of antibody interference or abnormal thyroid hormone-binding proteins. To identify antibody interference, we repeated the immunoassay using varied platforms and assay methods. The total T3 levels which were high in one-step immunoassay normalized in two-step immunoassay. On further evaluation, the patient was diagnosed with multiple myeloma and the antibody interference was secondary to IgG monoclonal antibody binding specifically to analog T3 leading to spurious results. Ours is the first report from India and the fourth case in literature to report a multiple myeloma antibody interfering with TFTs.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
