A Comparison of Chemiluminescent Microparticle Immunoassay (CMIA) and Electrochemiluminescence Immunoassay (ECLIA) for Thyroid Stimulating Hormone Receptor Antibodies (TSH Receptor Antibodies)

Abstract

Thyroid stimulating hormone receptor (TSHR) antibodies are one of immunological biomarkers for hyperthyroidism investigation, especially in the evaluation of Graves’ disease. The TSHR antibodies remarkably involved the pathogenesis of Graves’ disease by the binding of TSHR (TSHR agonists) and resulted in up-regulated thyroid hormone production.  Consequently, the TSHR antibodies have been used  as a diagnostic tool and follow-up marker in most patients with Graves’ disease. However, the heterogeneous assays of TSHR antibody detections in lab-to-lab probably have some effect on the result interpretation. This study aimed to compare the TSHR antibody results from patients with Graves’ disease (n=309) carried out by two different operating assays; including an electrochemiluminescence immunoassay (ECLIA) using Cobas E 801 (ATSHR) and chemiluminescent microparticle immunoassay (CMIA) using Alinity i (TRAb). The level of TSHR antibody detected by both ATSHR and TRAb were 0.81-39.50 (6.84 ± 7.45) IU/L and 0.82-48.34 (8.18 ± 8.26) IU/L, respectively. As a comparative analysis, this research demonstrated that both assays had approximately 94.5% consistency of results based on cross-tab analysis. Moreover, the results also provided strong correlation between the two assays (Cohen’s kappa and Spearman correlation test were 0.865 and 0.958, respectively). In terms of precision analysis, the within-run precisions from all levels of standard controls showed that the TRAb had lower coefficient of variation (CV) when compared to the ATSHR suggesting that the TRAb probably had slightly higher precision than the ATSHR in this study. In conclusion, this study indicated that the detection of TSHR antibodies can be measured by any of the two assays without giving  dissimilarity of results. However, each laboratory should evaluate the assays and study their own reference range prior to clinical use.