2nd generation assays are currently available to determine the concentration of thyrotropin receptor antibody (TRAb) present in Graves' disease. The aim of this study was to evaluate the analytical performance of TRAb assay on Elecsys 2010 and Cobas(R)e of Roche Diagnostics, a new test using electrochemiluminescence immunoassay (ECLIA). The analytical performance observed with this assay is accurate (repetability and reproductibility, analytical and functional sensitivities). Comparing this method with Brahms' assay (TRAK human RIA), the correlation observed can be put in the equation: y = 1.013 x + 1.381; r = 0.92. With a positive value in ECLIA at 0.9 UI/L and at 1 UI/L in RIA (functional sensitivity fixed by manufacturers), concordance study shows a false negative and two false positive. With a positive value at 0.8 UI/L with ECLIA (functional sensitivity calculated from precision's profile for a CV inferior to 10%), there is no false negative and two false-positive results, this value seems to give a better sensitivity.