Clinical evaluation of thyroglobulin Ⅱ assay and its impact on clinical management of thyroid diseases / 中华核医学与分子影像杂志

ABSTRACT

Objective To compare the consistence and difference between the assay results of the second generation of Tg (Tg Ⅱ) and the first generation of Tg (Tg Ⅰ) immunoassay,as well as to evaluate the impact of Tg Ⅱ on the clinical management of thyroid diseases.Methods Serum samples of 249 patients (30 with benign thyroid disorders and 219 with DTC;64 males and 185 females,average age 43.0 years)were collected and assayed by Tg Ⅱ and TgⅠ kits simultaneously.The measuring ranges of TgⅠ and TgⅡ were 0.10-1 000.00 μg/L and 0.04-500.00 μg/L,respectively.Data were analyzed by the Wilcoxon rank sum test and Spearman correlation analysis using IBM SPSS 19.0.Results The assay results of TgⅡ and TgⅠ strongly correlated (rs =0.979,P＜0.05).However,the median value of TgⅡ (2.31 (0.06-13.17) μg/L) was lower than that of TgⅠ(3.63(0.41-16.84) μg/L)(z=-13.25,P＜0.001).The difference between Tg Ⅱ and Tg Ⅰ got bigger when TgⅠ value decreased more.TgⅡ values were 11.09％ lower than TgⅠ (5.61(1.07-26.39) μg/L) vs 6.31(2.07-33.93) μg/L;z=-4.78,P＜0.05) in 30 patients with benign thyroid disorders and 37.71％ lower (2.18(0.07-7.47) μ.g/L) vs 3.50(0.39-10.18) μg/L;z=-9.02,P＜0.001) in 108 DTC patients without 131 Ⅰ treatment.But the above changes had no influence on clinical diagnosis and treatment.In the 71 DTC patients post 131Ⅰ treatment with low TSH and normal TgAb,there were 3 cases with TgⅠ＞1.0 μg/L but TgⅡ＜1.0μg/L,and 12 cases with TgⅠ＞0.1 μg/L but TgⅡ＜0.04 μg/L.Conclusions Serum TgⅡand Tg Ⅰ assay results are strongly correlated,though Tg Ⅱ value is slightly lower than Tg Ⅰ value.This difference may have no significant influence on the clinical diagnosis of thyroid diseases.However,TgⅡ may be better to evaluate the curative effect in some DTC patients post 131Ⅰ therapy.