2 CENTER EVALUATION OF 7 THYROTROPIN KITS USING LUMINESCENT DETECTION

We compared seven thyrotropin luminescent immunometric assay kits in t wo centres, by use of panel sera from 438 patients: controls (n = 203) and different groups of subjects: hyperthyroidism (n = 42), hypothyro idism (n = 46), non-thyroidal illness (n = 102), geriatrics (n = 24) a nd selected patients previously treated for thyroid cancer and maintai ned on suppressive doses of L-thyroxine (n = 17), anti-thyrotropin ant ibody (n = 4). We did not observe any significant differences in analy tical tests among the seven methods on the Probioqual control sera, An emia control serum and human serum pools. The linearity of serial dilu tions was found with all kits. Some variations were noticed at extreme dilutions. The within-assay precision was acceptable in all cases. Th e functional sensitivity limits were estimated from 20% compound preci sion profile: they ranged from 0.011 to 0.030 mU/l. In the clinical st udy, the seven assays demonstrated high diagnostic performance. Some i nterferences by heterophilic antibodies were observed.