Pre-evaluation and system optimization of the Elecsys (R) thyroid electrochemiluminescence immunoassays

We present the results of a pre-evaluation of the thyroid function test fre e thyroxine, free triiodothyronine and third generation TSH using the Elecs ys(R) electrochemiluminescence immunoassay system. A collaborative field st udy between the development center of the manufacturer and a clinical chemi stry laboratory addressed the reliability and comparability of the new Elec sys(R) assays to established methods under clinical laboratory conditions u sing samples from routine in vitro thyroid testing. Preliminary (reference) formulations of the reagents and several electrochemiluminescent pilot mod els were used for assay measurements, either in the company's research cent er or in the clinical setting. The new thyroid assays were compared with th e respective Enzymun-Test(R) assays, performed an the ES 300 automated immu noassay analyzer. A WHO standard was used for standardization of TSH, where as an equilibrium dialysis method was applied for free triiodothyronine. Th e free thyroxine assay was standardized against the Enzymun-Test(R) free th yroxine assay, which had previously been calibrated against equilibrium dia lysis. The aim of this field study was to support the optimization of the technolo gy used for Elecsys(R) in an early stage of development and thereby prepare the ground for the adaptation of the immunoassays to the final Elecsys(R) 2010 random access analyzer. A subsequent multicenter evaluation demonstrat ed that the requirements of routine thyroid testing in terms of reliability were fulfilled by the system.