Current Thyroglobulin Autoantibody (TgAb) Assays Often Fail to Detect Interfering TgAb that Can Result in the Reporting of Falsely Low/Undetectable Serum Tg IMA Values for Patients with Differentiated Thyroid Cancer
Current Thyroglobulin Autoantibody (TgAb) Assays Often Fail to Detect Interfering TgAb that Can Result in the Reporting of Falsely Low/Undetectable Serum Tg IMA Values for Patients with Differentiated Thyroid Cancer
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DOI：
10.1210/jc.2010-2762
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发表时间：
2011-05-01
影响因子：
5.8
通讯作者：
Fatemi, S.
中科院分区：
文献类型：
--
作者：
Spencer, C.;Petrovic, I.;Fatemi, S.
内容：在甲状腺球蛋白（Tg）检测之前，对样本进行甲状腺球蛋白抗体（TgAb）测定，因为定性TgAb状态（阳性或阴性）决定了Tg测定干扰的风险，并且定量TgAb浓度可作为分化型甲状腺癌的替代肿瘤标志物。目的：本研究评估了四种TgAb方法检测干扰TgAb的可靠性[根据异常低Tg免疫测定（IMA）判断]，方法：对来自所选和经鉴定的TgAb阴性和TgAb阳性的分化型甲状腺癌患者的血清，通过IMA和RIA测量血清Tg，并通过参考方法和三种附加方法测量TgAb。结果：当TgAb不存在时，Tg IMA和Tg RIA值是一致的。Tg IMA与Tg RIA比值低于75%被认为表明TgAb干扰。在可检测范围内设置了专家推荐的临界值，当用于确定是否存在TgAb时，将许多显示Tg干扰的标本错误分类为TgAb阴性。通过使用分析灵敏度（AS）作为TgAb的检测限，四种方法中的两种几乎消除了假阴性错误分类。不同标本的值之间的关系过于多变，以建立方法之间的转换factors.Conclusions：许多标本干扰TgAb被错误地归类为TgAb阴性，使用merger-recommended截止。建议使用测定AS限度检测TgAb，以尽量减少假阴性错误分类。然而，对于四种检测中的两种，AS限度在20-30%的情况下未能检测到干扰TgAb。TgAb方法在定性和定量方面变化太大，无法建立转换因子，从而在不破坏TgAb连续监测的情况下改变方法。（临床内分泌代谢杂志96：1283-1291，2011）
Context: Specimens have thyroglobulin antibody (TgAb) measured prior to thyroglobulin (Tg) testing because the qualitative TgAb status (positive or negative) determines risk for Tg assay interference, and the quantitative TgAb concentration serves as a surrogate tumor marker for differentiated thyroid cancer.Objective: This study assessed the reliability of four TgAb methods to detect interfering TgAb[as judged from abnormally low Tg immunometric assay (IMA) to Tg RIA ratios] and determine whether between method conversion factors might prevent a change in method from disrupting TgAb monitoring.Methods: Sera from selected and unselected TgAb-negative and TgAb-positive differentiated thyroid cancer patients had serum Tg measured by both IMA and RIA and TgAb measured by a reference method and three additional methods.Results: The Tg IMA and Tg RIA values were concordant when TgAb was absent. Tg IMA to Tg RIA ratios below 75% were considered to indicate TgAb interference. Manufacturer-recommended cutoffs were set in the detectable range, and when used to determine the presence of TgAb misclassified many specimens displaying Tg interference as TgAb negative. False-negative misclassifications were virtually eliminated for two of four methods by using the analytical sensitivity (AS) as the detection limit for TgAb. Relationships between values for different specimens were too variable to establish between-method conversion factors.Conclusions: Many specimens with interfering TgAb were misclassified as TgAb negative using manufacturer-recommended cutoffs. It is recommended that assay AS limits be used to detect TgAb to minimize false-negative misclassifications. However, for two of four assays, AS limits failed to detect interfering TgAb in 20-30% of cases. TgAb methods were too qualitatively and quantitatively variable to establish conversion factors that would allow a change in method without disrupting serial TgAb monitoring. (J Clin Endocrinol Metab 96: 1283-1291, 2011)