La Civita Evelina, Fiorenza Mariano, Jannuzzi Giuseppe, Polito Carmela, Sirica Rosa, Carbone Gianluigi, Sorvillo Domenica, Saviano Aniello, Terracciano Daniela
Department of Translational Medical Sciences, University of Naples "Federico II", Via S. Pansini, Naples, 5 - 80131, +39817462038, Italy.
Thyroid Res. 2025 Sep 9;18(1):44. doi: 10.1186/s13044-025-00261-8.
Serum thyroglobulin (Tg) is a key biomarker in the post-surgical monitoring of differentiated thyroid cancer (DTC). However, inter-assay variability among different immunoassay platforms can impact clinical interpretation, particularly at low Tg concentrations. This study aimed to compare the analytical performance and concordance of three widely used Tg immunoassays, Access (Beckman Coulter, Tg-B), Atellica (Siemens, Tg-A), and Liaison (Diasorin, Tg-L), with a focus on their agreement across clinically relevant Tg ranges.
A total of 103 residual serum samples from subjects with or without thyroid pathology were analyzed using Tg-B, Tg-A, and Tg-L. Correlation analysis, Bland-Altman plots, and concordance rates were evaluated across three Tg concentration intervals: <2 ng/mL, 2-50 ng/mL, and > 50 ng/mL. Tg-B was used as the reference method for comparison.
All three assays demonstrated strong overall correlations. Tg-L showed a very strong correlation with Tg-B (ρ = 0.89), with moderate agreement at Tg < 2 ng/mL. Tg-A also correlated well with Tg-B (ρ = 0.92), though agreement declined slightly at higher concentrations (> 50 ng/mL). The concordance rate for detecting undetectable Tg (< 0.2 ng/mL) was 96% for Tg-L and 98% for Tg-A when compared to Tg-B. Bland-Altman analysis revealed a significant negative bias for Tg-L versus Tg-B, while Tg-A and Tg-B showed no significant difference. A significant discrepancy was also observed between Tg-L and Tg-A.
Although the three Tg immunoassays demonstrated high correlation, notable differences emerged at lower and higher Tg levels, likely due to assay-specific antibody characteristics and calibrator variability. Our findings underscore the need for re-baselining when switching methods in longitudinal follow-up. However, the use of residual serum samples from a heterogeneous population, including individuals with and without thyroid pathology limits the direct clinical generalizability of the results and underscores the need for further validation in well-characterized post-thyroidectomy DTC cohorts.
血清甲状腺球蛋白（Tg）是分化型甲状腺癌（DTC）术后监测的关键生物标志物。然而，不同免疫分析平台之间的检测间变异性会影响临床解读，尤其是在低Tg浓度时。本研究旨在比较三种广泛使用的Tg免疫分析方法，即Access（贝克曼库尔特公司，Tg-B）、Atellica（西门子公司，Tg-A）和Liaison（索灵公司，Tg-L）的分析性能和一致性，重点关注它们在临床相关Tg范围内的一致性。
使用Tg-B、Tg-A和Tg-L对103份来自有或无甲状腺疾病受试者的残余血清样本进行分析。在三个Tg浓度区间：<2 ng/mL、2 - 50 ng/mL和>50 ng/mL内评估相关性分析、布兰德-奥特曼图和一致性率。以Tg-B作为比较的参考方法。
所有三种检测方法总体相关性都很强。Tg-L与Tg-B显示出非常强的相关性（ρ = 0.89），在Tg < 2 ng/mL时一致性中等。Tg-A与Tg-B也有良好的相关性（ρ = 0.92），不过在较高浓度（>50 ng/mL）时一致性略有下降。与Tg-B相比，Tg-L检测不可检测的Tg（<0.2 ng/mL）的一致性率为96%，Tg-A为98%。布兰德-奥特曼分析显示，与Tg-B相比，Tg-L存在显著的负偏差，而Tg-A和Tg-B无显著差异。Tg-L和Tg-A之间也观察到显著差异。
虽然三种Tg免疫分析方法显示出高度相关性，但在较低和较高Tg水平出现了显著差异，这可能归因于检测方法特异性抗体特性和校准物变异性。我们的研究结果强调在纵向随访中更换方法时需要重新建立基线。然而，使用来自包括有和无甲状腺疾病个体的异质人群的残余血清样本限制了结果的直接临床可推广性，并强调需要在特征明确的甲状腺切除术后DTC队列中进行进一步验证。
