Diagnostic accuracy of a new fluoroenzyme immunoassay for the detection of TSH receptor autoantibodies in Graves’ disease

Abstract

PurposeThyrotropin receptor (TSHR) autoantibodies (TRAbs) are a hallmark of Graves’ disease (GD). The aim of this study was to evaluate the diagnostic accuracy of a new third generation automatic fluorescence enzyme immunoassay for TRAb measurement in GD, in comparison with two current IMAs.MethodsSera of 439 subjects (57 patients with untreated GD, 34 with treated GD, 15 with GD and Graves’ orbitopathy, 52 with multinodular non-toxic goiter, 86 with Hashimoto’s thyroiditis, 20 with toxic adenoma or toxic multinodular goiter, 55 with non-thyroid autoimmune diseases and 120 normal controls) were tested for TRAbs with the ELiA™ anti-TSH-R assay (ThermoFischer Scientific, Uppsala, Sweden), the TRAK™ RIA, Brahms (Thermo Scientific, Hennigsdorf, Germany) and the Immulite™ TSI assay (Siemens Healthcare, Llanberis, UK).ResultsSensitivity and specificity of the ELiA™ anti-TSH-R assay, TRAK™ RIA and Immulite™ TSI assay were 94.7% and 99.6, 100 and 98.2%, 100 and 98.2%, respectively. Spearman’s coefficient and Passing-Bablok regression showed a satisfactory correlation between EliA™ and TRAK™ [rho: 0.925; 95% CI: 0.883-0-953. Intercept: − 0.875 (95% CI: − 2.411 to 0.194); slope: 1.086 (95% CI: 0.941 to 1.248)], and between ELiA™ and TSI™ [rho: 0.947; 95% CI: 0.912 0.969. intercept: 1.085 (95% CI: 0.665 to 2.116); slope 1.315 (95% CI:1.116 to 1.700)].ConclusionsThe diagnostic performance of ELiA™-TSH-R assay is comparable to that of some current TRAb assays. It may be adopted into clinical practice for the differential diagnosis of hyperthyroidism, to screen for transient hyperthyroidism, and to monitor disease activity and treatment effects.

A novel third-generation TSH receptor antibody (TRAb) enzyme-linked immunosorbent assay based on a murine monoclonal TSH receptor-binding antibody

“…First of all, this was due to the higher number of positive HT patients (8/56, 14.3%) in this TRAb ELISA which was slightly higher than the 10% in average reported elsewhere [3,7]. In contrast, a recently published third-generation TRAb fluoroenzyme assay employing a mouse recombinant mAb did not detect elevated TRAb in HT, whereas a radioimmunometric as well as a bridge TRAb assay did in that study [11].…”

“…The generation of mAbs directed against the TSH receptor which could be used for the immobilization thereof onto solid phases without interfering with the TSH binding and mAbs inhibiting TSH binding ushered in the era of competitive binding third-generation TRAb assays [2,6,11,[18][19][20]. The thyroid-stimulating human mAb M22 derived from peripheral blood mononuclear cells of a GD patient was employed to set up the first third-generation TRAb ELISA [15,21].…”

“…Recently, a non-competitive TRAb bridge assay was reported which demonstrated similar assay performance like competitive binding assay variants [11]. Notably, both competitive and non-competitive TRAb assays do not differentiate TBAb from TSAb [22][23][24].…”

“…Competitive binding TRAb assays depend on TRAb inhibition of labeled TSH binding to TSHR preparations in fluid phase (first generation) or immobilized TSHR on solid phases (second generation) [6][7][8][9]. Third-generation competitive TRAb assays use immobilized TSHR for bound/free separation and monoclonal antibodies (mAbs) like the human stimulatory moAb M22 or recombinant mouse mAb mimicking the binding of TSH to the TSHR for the competitive assay environment [10,11]. There has been a continuous improvement of assay performance from test generation to test generation [12].…”

Receptor autoimmunity: diagnostic and therapeutic implications

“…Due to the progressive improvement of accuracy of bioassay and immunoassay methods, it's now definitively demonstrated that the laboratory methods are the first choice in current diagnostic approaches, for clinical, analytical, and economic reasons [23][24][25][26][27][28].…”