We report the results of validation of canine serum cortisol determination with the Immulite 2000 Xpi cortisol immunoassay (Siemens), with characterization of precision (CV), accuracy (spiking-recovery [SR] bias), and observed total error (TEo = bias + 2CV) across the reportable range, specifically at the most common interpretation thresholds for dynamic testing. Imprecision increased at increasing rate with decreasing serum cortisol concentration and bias was low, resulting in increasing TEo with decreasing serum cortisol concentration. Inter-laboratory comparison study allowed for determination of range-based bias (RB) and average bias (AB). At 38.6 and 552 nmol/L (1.4 and 20 μg/dL), between-run CV was 10% and 7.5%, respectively, and TEo ~30% and ~20%, respectively (TEo remained similar regardless of the considered bias: SR, RB, or AB). These analytical performance parameters should be considered in the interpretation of results and for future expert consensus discussions to determine recommendations for allowable total error (TEa). Importantly, the commonly used thresholds for interpretation of results were determined ~40 y ago with different methods of measurements and computation, hence updating is desirable. Quality control material (QCM) had between-run imprecision of 4% for QCM1 and 7% for QCM2; the bias was minimal for both levels. Acceptable QC rules are heavily dependent on the desired TEa for the QCM system (TEa_QCM), itself limited by the desired clinical TEa. At low TEa_QCM (20–33%), almost no rules were acceptable, whereas at high TEa_QCM (50%), almost all rules were acceptable; further investigation is needed to determine which TEa_QCM can be guaranteed by simple QC rules.

我们报告了使用 Immulite 2000 Xpi 皮质醇免疫测定法 (Siemens) 对犬血清皮质醇测定进行验证的结果，包括精确度 (CV)、准确度（尖峰恢复 [SR] 偏差）和观察到的总误差（TEo = 偏差 + 2CV) 在可报告范围内，特别是在动态测试的最常见解释阈值下。随着血清皮质醇浓度的降低，不精确性以增加的速度增加，并且偏差很低，导致随着血清皮质醇浓度的降低，TEo 增加。实验室间比较研究允许确定基于范围的偏差 (RB) 和平均偏差 (AB)。在 38.6 和 552 nmol/L（1.4 和 20 μg/dL）下，运行间 CV 分别为 10% 和 7.5%，TEo 分别为 ~30% 和 ~20%（无论考虑的偏差如何，TEo 保持相似： SR、RB 或 AB）。在解释结果和未来专家共识讨论中应考虑这些分析性能参数，以确定允许总误差 (TEa) 的建议。重要的是，用于解释结果的常用阈值是在大约 40 年前用不同的测量和计算方法确定的，因此需要更新。质量控制材料 (QCM) 的运行间不精密度对于 QCM1 为 4%，对于 QCM2 为 7%；两个级别的偏差都很小。可接受的 QC 规则在很大程度上取决于 QCM 系统所需的 TEa (TEa 用于解释结果的常用阈值是在大约 40 年前用不同的测量和计算方法确定的，因此需要更新。质量控制材料 (QCM) 的运行间不精密度对于 QCM1 为 4%，对于 QCM2 为 7%；两个级别的偏差都很小。可接受的 QC 规则在很大程度上取决于 QCM 系统所需的 TEa (TEa 用于解释结果的常用阈值是在大约 40 年前用不同的测量和计算方法确定的，因此需要更新。质量控制材料 (QCM) 的运行间不精密度对于 QCM1 为 4%，对于 QCM2 为 7%；两个级别的偏差都很小。可接受的 QC 规则在很大程度上取决于 QCM 系统所需的 TEa (TEa_QCM )，其本身受到所需临床 TEa 的限制。在低 TEa _QCM (20–33%) 下，几乎没有任何规则是可以接受的，而在高 TEa _QCM (50%) 下，几乎所有规则都可以接受；需要进一步调查以确定哪些 TEa _QCM可以通过简单的 QC 规则得到保证。