Critical aspects of immunoradiometric thyroglobulin assays.

Background and aim of the studyThyroglobulin (Tg) evaluation is currently used in the follow-up of patients with differentiated thyroid carcinoma (DTC), but the measurement methods are flawed by analytical inaccuracy. In this paper we describe the results of a comparison between seven different immunoradiometric assays (IRMAs) for Tg determination.Material and methodsTg was measured in 50 patients with DTC by means of the following commercially available IRMA kits: HTGK-2 (DiaSorin), Tg IRMA (Schering-CIS bio international), ELSA-hTG (Schering-CIS bio international), Tg IRMA C.T. (ICN Pharmaceuticals), SELco Tg (Medipan Diagnostica), Tg Bridge IRMA (Adaltis) and IRMA-mat Tg (BYK-Sangtec Diagnostica). The distribution of the Tg values measured by the different IRMAs was compared and a correlation analysis was performed.ResultsThe Tg values were widely dispersed and the classification of patients according to Tg concentrations of clinical relevance varied depending on the IRMA used.ConclusionDespite efforts...