Liu Jen-Pei, Lu Li-Tien, Liao C T
Division of Biometry, Department of Agronomy, National Taiwan University, Taipei, Taiwan.
J Biopharm Stat. 2009 Sep;19(5):763-78. doi: 10.1080/10543400903105166.
Intermediate precision is one of the most important characteristics for evaluation of precision in assay validation. The current methods for evaluation of within-device precision recommended by the Clinical Laboratory Standard Institute (CLSI) guideline EP5-A2 are based on the point estimator. On the other hand, in addition to point estimators, confidence intervals can provide a range for the within-device precision with a probability statement. Therefore, we suggest a confidence interval approach for assessment of the within-device precision. Furthermore, under the two-stage nested random-effects model recommended by the approved CLSI guideline EP5-A2, in addition to the current Satterthwaite's approximation and the modified large sample (MLS) methods, we apply the technique of generalized pivotal quantities (GPQ) to derive the confidence interval for the within-device precision. The data from the approved CLSI guideline EP5-A2 illustrate the applications of the confidence interval approach and comparison of results between the three methods. Results of a simulation study on the coverage probability and expected length of the three methods are reported. The proposed method of the GPQ-based confidence intervals is also extended to consider the between-laboratories variation for precision assessment.
中间精密度是分析方法验证中精密度评估的最重要特征之一。临床实验室标准协会（CLSI）指南EP5-A2推荐的当前评估仪器内精密度的方法基于点估计量。另一方面，除了点估计量外，置信区间还可以通过概率陈述为仪器内精密度提供一个范围。因此，我们建议采用置信区间方法来评估仪器内精密度。此外，在CLSI批准的指南EP5-A2推荐的两阶段嵌套随机效应模型下，除了当前的萨特思韦特近似法和修正大样本（MLS）方法外，我们应用广义枢轴量（GPQ）技术来推导仪器内精密度的置信区间。CLSI批准的指南EP5-A2中的数据说明了置信区间方法的应用以及三种方法结果的比较。报告了三种方法的覆盖概率和预期长度的模拟研究结果。基于GPQ的置信区间的建议方法也被扩展以考虑实验室间精密度评估的差异。
