Department of Laboratory Medicine, Endocrine Laboratory, Amsterdam UMC Location University of Amsterdam, Meibergdreef, Amsterdam, The Netherlands.
Amsterdam Gastroenterology, Endocrinology & Metabolism, Amsterdam, The Netherlands.
Eur Thyroid J. 2023 Sep 14;12(5). doi: 10.1530/ETJ-23-0123. Print 2023 Oct 1.
International guidelines concerning subclinical hyperthyroidism and thyroid cancer advice absolute cut-off values for aiding clinical decisions in the low range of thyroid-stimulating hormone (TSH) concentrations. As TSH assays are known to be poorly standardized in the normal to high range, we performed a TSH assay method comparison focusing on the low range.
Sixty samples, selected to cover a wide range of TSH concentrations (<0.01 to 120 mIU/L) with oversampling in the lower range (<0.4 mIU/L), were used for the method comparison between three TSH immunoassays (Cobas, Alinity and Atellica). In addition, 20 samples were used to assess the coefficient of variation from duplicate measurements in these three methods.
The TSH immunoassays showed standardization differences with a bias of 7-16% for the total range and 1-14% for the low range. This could lead to a different classification of 1.5% of all measured TSH concentrations <0.40 mIU/L measured in our laboratory over the last 6 months, regarding the clinically important cut-off value of TSH = 0.1 mIU/L. As the imprecision of the immunoassays varied from 1.6-5.5%, this could lead to a similar reclassification as the bias between immunoassays.
We established the standardization differences of frequently used TSH assays for the total and low concentration ranges. Based on the proportional bias and the imprecision, this effect seems to have limited clinical consequences for the low TSH concentration range. Nevertheless, as guidelines mention absolute TSH values to guide clinical decision-making, caution must be applied when interpreting values close to these cut-offs.
国际关于亚临床甲状腺功能亢进和甲状腺癌的指南建议，在促甲状腺激素（TSH）浓度的低范围内，使用绝对临界值来辅助临床决策。由于 TSH 检测在正常到高范围内的标准化程度较差，因此我们进行了 TSH 检测方法比较，重点关注低范围。
选择 60 个样本，涵盖广泛的 TSH 浓度范围（<0.01 至 120 mIU/L），并在低浓度范围（<0.4 mIU/L）进行过采样，用于三种 TSH 免疫分析（Cobas、Alinity 和 Atellica）之间的方法比较。此外，使用 20 个样本评估这三种方法中重复测量的变异系数。
TSH 免疫分析显示标准化差异，总范围的偏差为 7-16%，低范围的偏差为 1-14%。这可能导致在过去 6 个月中，我们实验室测量的所有<0.40 mIU/L 的 TSH 浓度中，有 1.5%的分类不同，因为 TSH=0.1 mIU/L 是临床重要的截断值。由于免疫分析的不精密度从 1.6-5.5%不等，这可能导致与免疫分析之间的偏差类似的重新分类。
我们确定了常用 TSH 分析在总浓度范围和低浓度范围的标准化差异。基于比例偏差和不精密度，这种效应似乎对低 TSH 浓度范围的临床后果有限。然而，由于指南提到绝对 TSH 值来指导临床决策，因此在解释接近这些临界值的数值时必须谨慎。
