Comparison of new different assay systems for thyrotropin receptor antibodies with reference to thyroid-stimulating antibodies and thyroid stimulation-blocking antibodies in Graves' disease.

The aim of our study was to evaluate the diagnostic sensitivity of the new thyrotropin receptor antibody (TRAb) assays (Cosmic TRAb CT, ELISA and Yamasa DYNOtest TRAb). TRAb was positive in 43 of 44 (97.7%) untreated patients with Graves' disease by both TRAb CT and/or ELISA and NYNOtest TRAb. Thus the new TRAb assays were clearly more sensitive than the conventional assay (positivity: 85%). There was a strong positive correlation between the data obtained in TRAb CT and/or ELISA and those obtained in DYNOtest TRAb (r = 0.942, p < 0.0001). There was a significant correlation between the new TRAb and TSAb (r = 0.696, p < 0.0001). Although there was a significant correlation between the new TRAb and thyroid stimulation-blocking antibody (TSBAb), the correlation coefficient was low (r = 0.605, p < 0.0001). The increased sensitivity of the new TRAb assays for Graves' disease provides an advantage over conventional assay.