采用全自动预处理工艺的甲状腺球蛋白免疫测定法可在抗甲状腺球蛋白抗体阳性标本中提供准确的甲状腺球蛋白值。

Thyroglobulin immunoassay with a fully automated pretreatment process provides accurate thyroglobulin values in anti-thyroglobulin antibody positive specimens.

机构信息

Development Division, FUJIREBIO INC., Tokyo, Japan.

Development Division, Advanced Life Science Institute, Inc., Tokyo, Japan.

出版信息

Clin Biochem. 2023 Aug;118:110598. doi: 10.1016/j.clinbiochem.2023.110598. Epub 2023 Jun 16.

DOI:10.1016/j.clinbiochem.2023.110598

PMID:37330000

Abstract

OBJECTIVES

Human thyroglobulin (Tg) is widely used as a tumor marker for recurrence and metastasis of differentiated thyroid cancer (DTC). Currently, serum Tg values are measured using second-generation sandwich immunoassays (2nd-IMA). However, interference by endogenous autoantibodies to thyroglobulin (TgAbs) can lead to false-negative results or falsely low Tg values. Here, we describe a new Tg assay using the immunoassay for total antigen including complex via pretreatment (iTACT) method to prevent TgAb interference and compare it with 2nd-IMA.

METHODS

Tg values were evaluated by three assays: iTACT Tg, Elecsys Tg-II, which is a 2nd-IMA, and LC-MS/MS (Liquid chromatography tandem-mass spectrometry). The ratio of Tg values between each assay was then compared to the Tg value by LC-MS/MS and TgAb titer. Tg immunoreactivity was analyzed by size-exclusion chromatography.

RESULTS

Correlation between iTACT Tg and LC-MS/MS using TgAb-positive specimens was good: Passing-Bablok regression with iTACT Tg = 1.084 × LC-MS/MS + 0.831. Correlation between 2nd-IMA and LC-MS/MS showed a relatively lower slope: 2nd-IMA = 0.747 × LC-MS/MS - 0.518. Thus, Tg values determined by iTACT Tg are equivalent to those of LC-MS/MS regardless of TgAb titer, whereas 2nd-IMA gave lower Tg values due to TgAb interference. Tg-TgAb complexes of various molecular weights were verified by size-exclusion chromatography. Tg values measured by 2nd-IMA fluctuated depending on the molecular weight of the Tg-TgAb complexes, whereas iTACT Tg accurately quantified Tg values regardless of the size of the Tg-TgAb complexes.

CONCLUSION

Tg values in TgAb-positive specimens were accurately determined by iTACT Tg. TgAb-positive specimens contain Tg-TgAb complexes of various molecular weights that interfere with Tg value determination by 2nd-IMA, whereas iTACT Tg is unaffected by the presence of Tg-TgAb complexes.

摘要

目的

人甲状腺球蛋白（Tg）被广泛用作分化型甲状腺癌（DTC）复发和转移的肿瘤标志物。目前，血清 Tg 值采用第二代夹心免疫分析法（2 代-IMA）进行测量。然而，内源性抗甲状腺球蛋白自身抗体（TgAbs）的干扰可能导致假阴性结果或 Tg 值假性降低。在这里，我们描述了一种使用通过预处理（iTACT）方法检测总抗原的免疫分析来预防 TgAb 干扰的新 Tg 检测方法，并将其与 2 代-IMA 进行比较。

方法

通过三种检测方法评估 Tg 值：iTACT Tg、Elecsys Tg-II（第二代 IMA）和 LC-MS/MS（液相色谱串联质谱）。然后将每种检测方法的 Tg 值比值与 LC-MS/MS 和 TgAb 滴度的 Tg 值进行比较。通过分子筛色谱分析 Tg 免疫反应性。

结果

iTACT Tg 与 TgAb 阳性标本的 LC-MS/MS 之间相关性良好：Passing-Bablok 回归 iTACT Tg=1.084×LC-MS/MS+0.831。2 代-IMA 与 LC-MS/MS 之间的相关性显示出较低的斜率：2 代-IMA=0.747×LC-MS/MS-0.518。因此，无论 TgAb 滴度如何，iTACT Tg 测定的 Tg 值与 LC-MS/MS 相当，而 2 代-IMA 由于 TgAb 干扰导致 Tg 值较低。通过分子筛色谱验证了各种分子量的 Tg-TgAb 复合物。2 代-IMA 测定的 Tg 值随 Tg-TgAb 复合物的分子量而波动，而 iTACT Tg 则不受 Tg-TgAb 复合物大小的影响，准确地定量了 Tg 值。