Southern Adelaide Diabetes and Endocrine Services, Repatriation General Hospital, Daw Park, Adelaide 5041, Australia.
J Clin Endocrinol Metab. 2013 May;98(5):1883-90. doi: 10.1210/jc.2012-3576. Epub 2013 Mar 28.
Measurement of plasma cortisol by immunoassay after ACTH₁₋₂₄ stimulation is used to assess the hypothalamic-pituitary-adrenal (HPA) axis. Liquid chromatography-tandem mass spectrometry (LCMS) has greater analytical specificity than immunoassay and equilibrium dialysis allows measurement of free plasma cortisol.
We investigated the use of measuring total and free plasma cortisol by LCMS and total cortisol by immunoassay during an ACTH₁₋₂₄ stimulation test to define HPA status in pituitary patients.
This was a case control study conducted in a clinical research facility.
We studied 60 controls and 21 patients with pituitary disease in whom HPA sufficiency (n = 8) or deficiency (n = 13) had been previously defined.
Participants underwent 1 μg ACTH(1-24) intravenous and 250 μg ACTH₁₋₂₄ intramuscular ACTH₁₋₂₄ stimulation tests.
Concordance of ACTH₁₋₂₄-stimulated total and free plasma cortisol with previous HPA assessment.
Total cortisol was 12% lower when measured by immunoassay than by LCMS. Female sex and older age were positively correlated with ACTH₁₋₂₄-stimulated total and free cortisol, respectively. Measurements of total cortisol by immunoassay and LCMS and free cortisol 30 minutes after 1 μg and 30 and 60 minutes after 250 μg ACTH₁₋₂₄ were concordant with previous HPA axis assessment in most pituitary patients. However, free cortisol had greater separation from the diagnostic cutoff than total cortisol.
Categorization of HPA status by immunoassay and LCMS after ACTH₁₋₂₄ stimulation was concordant with previous assessment in most pituitary patients. Free cortisol may have greater clinical use in patients near the diagnostic threshold.
促肾上腺皮质激素 1-24（ACTH₁₋₂₄）刺激后通过免疫测定法测量血浆皮质醇，用于评估下丘脑-垂体-肾上腺（HPA）轴。液相色谱-串联质谱（LCMS）比免疫测定法具有更高的分析特异性，平衡透析法可测量游离血浆皮质醇。
我们通过 LCMS 测量 ACTH₁₋₂₄ 刺激试验期间的总游离和游离血浆皮质醇以及免疫测定法的总皮质醇，以确定垂体疾病患者的 HPA 状态。
这是在临床研究机构进行的病例对照研究。
我们研究了 60 名对照者和 21 名垂体疾病患者，其中先前已确定 HPA 充足（n = 8）或不足（n = 13）。
参与者接受了 1μg ACTH(1-24)静脉内和 250μg ACTH₁₋₂₄ 肌肉内 ACTH₁₋₂₄ 刺激试验。
ACTH₁₋₂₄ 刺激后的总游离和游离血浆皮质醇与先前的 HPA 评估的一致性。
与 LCMS 相比，免疫测定法测量的总皮质醇低 12%。女性性别和年龄较大与 ACTH₁₋₂₄ 刺激后的总游离皮质醇分别呈正相关。大多数垂体患者中，1μg 后 30 分钟和 250μg 后 30 分钟和 60 分钟时的免疫测定法和 LCMS 总皮质醇以及游离皮质醇的测量与先前的 HPA 轴评估一致。然而，游离皮质醇与诊断截止值的分离度大于总皮质醇。
在大多数垂体患者中，ACTH₁₋₂₄ 刺激后通过免疫测定法和 LCMS 分类 HPA 状态与先前的评估一致。游离皮质醇在接近诊断阈值的患者中可能具有更大的临床用途。
