The Experimental And Clinical Studies Of Serum Thyroglobulin And Thyroglobulin Antibody

Objective This first part of this paper was to compare the difference between the assay results of the second generation thyroglobulin?Tg???Roche Diagnostic?and the first generation Tg?Tg??immunoassay,and to evaluate the impact of Tg? on the clinical management of thyroid diseases.According to 2015 ATA thyroid nodule and differentiated thyroid cancer?DTC?management guidelines,the second part was to evaluate the dynamic variations of excellent response rates?ERR?in patients with papillary thyroid microcarcinoma?PTMC?who underwent ¹³¹I therapy by using two cut-off values of serum TgAb for excellent response?ER?judgments,and to evaluate the impact of the serum TgAb on the treatment assessment after ¹³¹I therapy.Methods A total of 249 patients were enrolled in the first part of the study.Serum samples were assayed by Tg? and Tg? kits at the same time,and compared the difference between the assay results of Tg? and Tg?.In the second part of the study we assumed that cut-off value of serum TgAb in two levels were both negative,thus,we classified ER standards into two types,?I?Tg<0.2ng/mL,TgAb<10.0KIU/L and?II?Tg<0.2ng/mL,TgAb<115.0KIU/L,and with no anomalies by ultrasonography.There were 45 patients with PTMC were enrolled in this study.According to ER standards designed in this study,ERRs at 1,4 and 10 month?s?after ¹³¹I therapy were calculated.Results The assay results of serum Tg? and Tg? were highly correlated?rs=0.979,P<0.05?.However,the median value of serum Tg? was 2.3?0.06¹3.2?ng/mL,which was lower than that of Tg? 3.6?0.4¹6.8?ng/mL?Z=-13.3,P<0.001?.Among the serum samples from 71 DTC patients who were treated with ¹³¹I and their serum TgAb were less than 115.0KIU/L?on TSH suppression?,3 cases were found with Tg?>1.0 ng/mL but Tg?<1.0 ng/mL and 12 cases were with Tg?>0.1 ng/mL but Tg?<0.04 ng/mL.Before ¹³¹I therapy?on TSH stimulation?,84.4%?38/45?patients with PTMC were defined with positive TgAb when using cut-off 10.0KIU/L,but fell to 15.6%?7/45?when using cut-off 115.0KIU/L,and the difference was statistically significant?P<0.001?.With ER standards I and II,the ERR were 6.7%?3/45?vs 22.2%?10/45?1month after¹³¹I therapy?on TSH suppresion??P=0.036?,8.9%?4/45?vs 42.2%?19/45?4 months after ¹³¹I therapy?on TSH suppresion??P<0.001?,13.3%?6/45?vs 48.9%?22/45?10 months after ¹³¹I therapy?on TSH suppresion??P<0.001?respectively.Conclusions The results of serum Tg? and Tg? were highly correlated,but Tg? value was slightly lower than that of Tg?.There was no significant impact on clinical diagnosis and treatment of thyroid diseases.However,for some DTC patients who had undergone ¹³¹I therapy with low level Tg,Tg? might change the clinical management in follow-up.The different cut-offs of serum TgAb level made significant impacts on ERR in evaluating the treatment outcomes of PTMC patients after ¹³¹I therapy,and ERRs increased with the time.