Two centre evaluation of seven thyrotropin kits using luminescent detection.

Abstract

We compared seven thyrotropin luminescent immunometric assay kits in two centres, by use of panel sera from 438 patients: controls (n = 203) and different groups of subjects: hyperthyroidism (n = 42), hypothyroidism (n = 46), non-thyroidal illness (n = 102), geriatrics (n = 24) and selected patients previously treated for thyroid cancer and maintained on suppressive doses of L-thyroxine (n = 17), anti-thyrotropin antibody (n = 4). We did not observe any significant differences in analytical tests among the seven methods on the Probioqual control sera, Anemia control serum and human serum pools. The linearity of serial dilutions was found with all kits. Some variations were noticed at extreme dilutions. The within-assay precision was acceptable in all cases. The functional sensitivity limits were estimated from 20% compound precision profile: they ranged from 0.011 to 0.030 mU/l. In the clinical study, the seven assay demonstrated high diagnostic performance. Some interference by heterophilic antibodies were observed.