Multiplexed immunoassay of thyroglobulin autoantibodies in patients with differentiated thyroid carcinoma.

BACKGROUND Thyroglobulin (Tg) antibodies (TgAb) screening is recommended in patients with differentiated thyroid carcinoma (DTC) to validate Tg measurements. We compared a new multiplexed and 2 conventional TgAb immunoassays in patients with DTC and healthy controls. METHODS TgAb were measured by 2 conventional automated immunoassays and a multiplexed immunoassay in sera from 163 patients with DTC and 64 controls. RESULTS No significant differences were found between the different assays when the suggested manufacturer cutoffs were used. The positive rate of multiplexed assay, but not of conventional assays, significantly increased when limits of detection were used as cutoff. CONCLUSION Further technical evaluations are necessary to explain the very high rate of detectable TgAb values in both patients with DTC and controls by the multiplexed assay. For the moment, we suggest caution in using such methods in the current clinical practice.