Gal A, Weidgraaf K, Bowden J P, Lopez-Villalobos N, Cave N J, Chambers J P, Castillo-Alcala F
Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand.
J Vet Intern Med. 2017 May;31(3):711-716. doi: 10.1111/jvim.14710. Epub 2017 Apr 13.
The ACTH stimulation has low sensitivity for the diagnosis of hypercortisolism possibly as a result of biological and analytical variability.
HYPOTHESIS/OBJECTIVES: To report the components of biological and analytical variability in serum cortisol concentration post-ACTH stimulation ([cortisol]) in healthy dogs.
Fourteen healthy harrier hound dogs.
The data were extracted from a separate, prospective, randomized, double-blinded, controlled discovery study in which dogs treated with vehicle control and 4 different doses of cortisone acetate (CA) for 7 days had an ACTH stimulation test performed to confirm the dose-dependent effect of CA. The index of individuality (IoI), the critical difference between sequential measurements (C ), and the number of measurements required to assess the homeostatic set point (HSP) of [cortisol] with confidence intervals (CI) of 90 and 95% were estimated.
The IoI was equal to 1.1 and the C was 3.3 μg/dL (92 nmol/L). The number of measurements required to assess the HSP of [cortisol] with CI of 90 and 95% were 3 and 15, respectively. Additionally, mean [cortisol] was higher in males than in females (13.3 ± 4 μg/dL [366 ± 114 nmol/L] vs. 11.5 ± 2.5 μg/dL [318 ± 65 nmol/L], respectively; P = .046). As expected, treatment with CA resulted in a dose-dependent suppression of [cortisol].
False-negative test results in hypercortisolism could occur when [cortisol] is outside of the individual's HSP and within the reference interval. The large C emphasizes the importance of assessing clinically relevant parameters in the diagnosis and monitoring of HC.
促肾上腺皮质激素（ACTH）刺激试验对皮质醇增多症的诊断敏感性较低，这可能是生物和分析变异性导致的结果。
假设/目的：报告健康犬在ACTH刺激后血清皮质醇浓度（[皮质醇]）的生物和分析变异性组成部分。
14只健康的猎兔犬。
数据取自一项单独的、前瞻性、随机、双盲、对照的探索性研究，在该研究中，用赋形剂对照和4种不同剂量的醋酸可的松（CA）治疗犬7天，然后进行ACTH刺激试验以确认CA的剂量依赖性效应。估计个体指数（IoI）、连续测量之间的临界差异（C）以及以90%和95%置信区间（CI）评估[皮质醇]稳态设定点（HSP）所需的测量次数。
IoI等于1.1，C为3.3μg/dL（92nmol/L）。以90%和95%CI评估[皮质醇]HSP所需的测量次数分别为3次和15次。此外，雄性犬的平均[皮质醇]高于雌性犬（分别为13.3±4μg/dL[366±114nmol/L]和11.5±2.5μg/dL[318±65nmol/L]；P = 0.046）。正如预期的那样，CA治疗导致[皮质醇]呈剂量依赖性抑制。
当[皮质醇]超出个体HSP但在参考区间内时，可能会出现皮质醇增多症的假阴性检测结果。较大的C强调了在皮质醇增多症的诊断和监测中评估临床相关参数的重要性。
