Negative Thyrotropin Assay Interference Associated with an IgGκ Paraprotein

[摘要] Human anti-animal immunoglobulin or “heterophile” antibodies interfere in many immunoassays (1)(2). Anti-animal immunoglobulin antibodies can occur idiopathically or after treatment with monoclonal antibodies. Those heterophilic antibodies that bind murine immunoglobulins are often referred to as human anti-mouse antibodies (1). Two-site (sandwich) immunoassays are the assays most frequently reported to be subject to positive interference (1). False-negative heterophile interferences, to our knowledge, have all been cases of endogenous anti-analyte (not anti-immunoglobulin) antibodies or anti-idiotype antibodies in patients treated with monoclonal antibodies (3)(4)(5)(6). Here we describe a negative assay interference associated with an IgGκ paraprotein.The AxSYM Ultrasensitive hTSH II assay (Abbott Laboratories) is a sandwich assay for thyrotropin (TSH) that uses mouse monoclonal anti-TSH-coated microparticles and goat anti-TSH-alkaline phosphatase conjugate. In our laboratory, the functional detection limit of this assay is 0.1 mIU/L with a day-to-day CV of 12% (mean, 0.17 mIU/L).Inconsistent thyroid function test results in an 80-year-old male patient suffering from a myelodysplastic syndrome (IgGκ monoclonal …

[学科分类] 过敏症与临床免疫学