Evaluation of interference of thyroglobulin antibodies on the measurement of thyroglobulin by two chemiluminescence immunoassay / 中华检验医学杂志

ABSTRACT

Objective To investigate the interference of thyroglobulin antibodies ( TgAb ) on the measurement of thyroglobulin ( Tg) by 2 chemiluminescence immunoassays ( CLIAs) .Methods Data of 199 315 individuals with determined TgAb and Tg , including physical checkup subjects , differentiated thyroid carcinoma ( DTC) patients and patients with other diseases , were retrospectively collected in Peking Union Medical College Hospital from November 2012 to April 2015.The correlation between serum Tg level and serum TgAb concentration was analyzed and the positive rate of TgAb in physical checkup subjects was calculated.Furthermore, 290 serum samples with different TgAb concentration were applied in the recovery test by adding in confirmed serum Tg .The correlation between the recovery of confirmed serum Tg and TgAb concentrations was evaluated using Pearson correlation analysis .Results The serum Tg was all decreased with the elevated TgAb concentration in each group of subjects .The positive rate of TgAb was 10.84%(8 416/77 634) in physical checkup subjects .It was higher in females than in males and was increased with age.Recovery test showed that the average recoveries of confirmed serum Tg in TgAb-negative serum were 107.28%(86.30%-117.60%) and 107.94% (85.60%-124.10%) respectively in Roche and Beckman systems.But in TgAb-positive serum samples , the average recoveries in Roche and Beckman systems were 88.59% (35.85% -141.53%) and 95.77% (36.48% -131.78%) respectively, and 12.63%(24/190) and 13.68%(26/190) samples displayed a recovery less than 80%.The recovery rate of confirmed serum Tg showed a significantly negative correlation with elevated TgAb concentration , with r=-0.239 (P=0.001) in Roche and r=-0.251 (P<0.001) in Beckman.Conclusions TgAb-positive serum, especially with high concentration of TgAb , significantly interfered the measurement of Tg .Thus, serum TgAb should be determined together with serum Tg to explore whether there was an interference .To avoid misdiagnosis and inappropriate therapy , clinician should be informed once serum TgAb displayed positive.