The interference of Tg-Ab to Tg measurement in patients with differentiated thyroid carcinomas

Objectives This study to investigate the thyroglobulin antibody (Tg-Ab) interference with serum thyroglobulin (Tg) measurement of patients with differentiated thyroid carcinomas (DTCs).

Methods Tg positive serum (Tg positive,Tg-Ab undetectable) 1.6ml of the DTC patients were distributed to eight tubes(A-H) equally (200μl/tube). Varied concentrations TgAb positive serums (Tg-Ab 20-4000 IU/ml,Tg undetectable) of the DTC patients were added in the seven Tg positive serum tubes (B-H) respectively. Tube A included Tg positive serum 200μl and water 200μl. The thyroglobulin value of the eight tubes was determined by Roche electrode induce chemiluminescent emission system with monoclonal antibody sandwich analysis after incubating them for 12 hours in room temperature. The percent recoveries were calculated with the experimental Tg values of the eight tubes and their expected Tg values of each tubes.

Results The experimental Tg values of the Tg-Ab and Tg mixed serum were under the water and Tg mixed serum. The experimental Tg value is not decrease progressively when the Tg-Ab concentration increased from tube A to tube H.

Conclusions Thyroglobulin antibody interfere the thyroglobulin value in monoclonal antibody sandwich analysis. The Tg-Ab decreased the Tg value not in dose-dependent manner.

Research Support State Natural Science Foundation(30970859