Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, New York, United States; Current Address: Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States.
Department of Pathology, Wexner Medical Center, The Ohio State University, Columbus, Ohio, United States.
Endocr Pract. 2022 Jul;28(7):684-689. doi: 10.1016/j.eprac.2022.04.003. Epub 2022 Apr 26.
The accurate interpretation of the cosyntropin (adrenocorticotropic hormone [ACTH]) stimulation test requires method- and assay-specific cutoffs of the level of cortisol. Compared with a historical cutoff (18 μg/dL) for polyclonal antibody-based immunoassays, lower thresholds were proposed for the Roche Elecsys II assay, which uses a monoclonal antibody. However, cutoffs for other commonly adopted, monoclonal antibody-based cortisol assays were not yet available. Here, we established the thresholds for the level of cortisol specific to the Abbott Architect immunoassay by comparing the measurements of the level of cortisol using 3 immunoassays.
The ACTH stimulation test was performed in patients with suspected adrenal insufficiency (n = 50). The serum cortisol level was measured using the Abbott Architect, Roche Elecsys II, and Siemens Centaur assays. The results of the Abbott assay were also compared with those of liquid chromatography-tandem mass spectrometry. The receiver operating characteristic analysis was performed to derive new diagnostic thresholds for the Abbott assay using the polyclonal antibody-based Siemens assay as the reference method.
The concentrations of cortisol measured using the Abbott assay were similar to those measured using liquid chromatography-tandem mass spectrometry and the Roche Elecsys II assay but significantly lower than those measured using the Siemens assay. The optimized threshold for cortisol using the Abbott assay was 14.6 μg/dL at 60 minutes after stimulation (sensitivity, 92%; specificity, 96%) and 13.2 μg/dL at 30 minutes after stimulation (sensitivity, 100%; specificity, 89%).
We recommend a threshold of 14.6 μg/dL for the level of cortisol at 60 minutes after ACTH stimulation for the Abbott assay. In comparison with the historical threshold of 18 μg/dL, the application of the new cutoff may significantly decrease false-positive results due to ACTH stimulation testing. The use of assay-specific cutoffs will be essential for reducing misclassification and overtreatment in patients with suspected adrenal insufficiency.
准确解读促皮质素（促肾上腺皮质激素[ACTH]）刺激试验需要根据方法和检测方法特异性设定皮质醇水平的临界值。与多克隆抗体免疫分析法的历史临界值（18μg/dL）相比，罗氏 Elecsys II 检测法所使用的单克隆抗体提出了较低的阈值。然而，其他常用的单克隆抗体皮质醇检测法的临界值尚不清楚。在此，我们通过比较 3 种免疫分析法测量的皮质醇水平，建立了 Abbott Architect 免疫分析法特有的皮质醇水平的阈值。
对疑似肾上腺功能不全的患者（n=50）进行 ACTH 刺激试验。使用 Abbott Architect、罗氏 Elecsys II 和西门子 Centaur 检测法测量血清皮质醇水平。Abbott 检测法的结果还与液相色谱-串联质谱法进行了比较。采用基于多克隆抗体的西门子检测法作为参考方法，通过接收者操作特征分析得出 Abbott 检测法的新诊断阈值。
Abbott 检测法测量的皮质醇浓度与液相色谱-串联质谱法和罗氏 Elecsys II 检测法测量的浓度相似，但明显低于西门子检测法测量的浓度。使用 Abbott 检测法优化的皮质醇临界值为刺激后 60 分钟时 14.6μg/dL（敏感性 92%；特异性 96%）和刺激后 30 分钟时 13.2μg/dL（敏感性 100%；特异性 89%）。
我们建议在使用 Abbott 检测法时，将 ACTH 刺激后 60 分钟时的皮质醇水平设定为 14.6μg/dL 的阈值。与 18μg/dL 的历史阈值相比，新临界值的应用可能会显著减少因 ACTH 刺激试验而导致的假阳性结果。使用检测法特异性的临界值对于减少疑似肾上腺功能不全患者的误诊和过度治疗至关重要。
