Thyroglobulin and thyroglobulin autoantibodies measurement using the automated KRYPTOR® platform in patients with differentiated thyroid carcinoma.

The aim of the present study is 1) to compare our established manual thyroglobulin (Tg) and Tg autoantibody (TgAb) immunoassays to the automated KRYPTOR® platform from the same manufacturer, in a large group of DTC patients and 2) to evaluate whether a change in assay methods could be made without disrupting the serial monitoring pattern. Sera from 160 patients with histologically proven DTC were obtained and Tg and TgAb measured by manual immunoassays and a fully automated platform. We found an excellent agreement between the 2 methods for Tg measurement (R=0.9888, p<0.00001) with a 90% overall concordance rate. At the same time, a weak relationship was found between the two methods for TgAb measurement (R=0.4438, p<0.03). However, 151 patients had concordant results with a 94% overall concordance rate. In conclusion, the excellent correlation we found between the Tg assays make the fully automated KRYPTOR® Tg assay interchangeable with the established Dyno-test® Tg-plus in patients with DTC. A very high qualitative concordance rate was found between Dyno-test® TgAbn and KRYPTOR® TgAb assays, making these methods interchangeable to screen sera for the presence of TgAb. However, since quantitative discordances still occurred in some patients a re-baseline of TgAb positive patients is strongly supported before changing the TgAb assay method. Georg Thieme Verlag KG Stuttgart · New York.