Javorsky Bradley R, Raff Hershel, Carroll Ty B, Algeciras-Schimnich Alicia, Singh Ravinder Jit, Colón-Franco Jessica M, Findling James W
Endocrinology Center and Clinics, Froedtert & the Medical College of Wisconsin, Milwaukee, WI 53051, USA.
Division of Endocrinology and Molecular Medicine, Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
J Endocr Soc. 2021 Feb 18;5(4):bvab022. doi: 10.1210/jendso/bvab022. eCollection 2021 Apr 1.
The normal cortisol response 30 or 60 minutes after cosyntropin (ACTH) is considered to be ≥18 μg/dL (500 nmol/L). This threshold is based on older serum cortisol assays. Specific monoclonal antibody immunoassays or LC-MS/MS may have lower thresholds for a normal response.
To calculate serum cortisol cutoff values for adrenocorticotropic hormone (ACTH) stimulation testing with newer specific cortisol assays.
Retrospective analysis of ACTH stimulation tests performed in ambulatory and hospitalized patients suspected of adrenal insufficiency (AI). Serum samples were assayed for cortisol in parallel using Elecsys I and Elecsys II immunoassays, and when volume was available, by Access immunoassay and LC-MS/MS.
A total of 110 patients were evaluated. Using 18 μg/dL as the cortisol cutoff after ACTH stimulation, 14.5%, 29%, 22.4%, and 32% of patients had a biochemical diagnosis of AI using the Elecsys I, Elecsys II, Access, and LC-MS/MS assays, respectively. Deming regressions of serum cortisol were used to calculate new cortisol cutoffs based on the Elecsys I cutoff of 18 μg/dL. For 30-minute values, new cutoffs were 14.6 μg/dL for Elecsys II, 14.8 μg/dL for Access, and 14.5 μg/dL for LC-MS/MS. Baseline cortisol <2 μg/dL was predictive of subnormal stimulated cortisol values.
To reduce false positive ACTH stimulation testing, we recommend a new serum cortisol cutoff of 14 to 15 μg/dL depending on the assay used (instead of the historical value of 18 μg/dL with older polyclonal antibody assays). Clinicians should be aware of the new cutoffs for the assays available to them when evaluating patients for AI.
促肾上腺皮质激素（ACTH）刺激后30或60分钟时，正常的皮质醇反应被认为≥18μg/dL（500nmol/L）。该阈值基于较旧的血清皮质醇检测方法。特定的单克隆抗体免疫测定法或液相色谱-串联质谱法（LC-MS/MS）对于正常反应可能有较低的阈值。
使用更新的特定皮质醇检测方法计算促肾上腺皮质激素（ACTH）刺激试验的血清皮质醇临界值。
对怀疑肾上腺功能不全（AI）的门诊和住院患者进行的ACTH刺激试验进行回顾性分析。使用Elecsys I和Elecsys II免疫测定法并行检测血清样本中的皮质醇，并且在样本量充足时，通过Access免疫测定法和LC-MS/MS进行检测。
共评估了110例患者。以ACTH刺激后皮质醇临界值为18μg/dL时，分别使用Elecsys I、Elecsys II、Access和LC-MS/MS检测法，有14.5%、29%、22.4%和32%的患者被生化诊断为AI。基于Elecsys I临界值18μg/dL，采用血清皮质醇的戴明回归法计算新的皮质醇临界值。对于30分钟时的值，Elecsys II的新临界值为14.6μg/dL，Access为14.8μg/dL，LC-MS/MS为14.5μg/dL。基线皮质醇<2μg/dL可预测刺激后皮质醇值低于正常。
为减少ACTH刺激试验的假阳性，我们建议根据所使用的检测方法采用14至15μg/dL的新血清皮质醇临界值（而不是旧的多克隆抗体检测法的历史值18μg/dL）。临床医生在评估AI患者时应了解他们可用检测方法的新临界值。
