An appraisal of statistical procedures used in derivation of reference intervals
An appraisal of statistical procedures used in derivation of reference intervals
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DOI：
10.1515/cclm.2010.319
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发表时间：
2010-11-01
影响因子：
6.8
通讯作者：
Boyd, James C.
中科院分区：
文献类型：
--
作者：
Ichihara, Kiyoshi;Boyd, James C.
在进行研究以获得参考区间（RI）时，从计划阶段到最终计算RI的每个步骤通常都应用各种统计程序。确定必要的样本量是一个重要的考虑因素，建议在多中心研究中对每个亚组中至少400名个体进行评价，以建立可靠的常见RI。多元回归分析允许识别导致测试结果变化的最重要因素，同时考虑这些因素之间可能的混杂关系。在为判断划分参考值的必要性而提出的各种方法中，嵌套方差分析（ANOVA）是可能的选择方法，因为它能够处理多个组并能够调整多个因素。Box-Cox幂变换通常用于将数据转换为高斯分布，以用于RI的参数计算。然而，这种转变偶尔会失败。因此，建议普遍使用基于数据排序后确定2.5和97.5百分位数的非参数方法。Box-Cox变换的性能可以通过引入表示变换原点的附加参数来提高。在模拟中，由参数方法计算的参考限（RL）的置信区间（CI）比由非参数方法计算的置信区间窄。然而，由于Box-Cox转换参数估计引入的参数确定RL的额外变异性，差异幅度相当小。参数计算方法在允许识别和排除RI计算期间的极值方面可能比非参数方法具有优势。临床化学实验室医学2010;48：1537-51。
When conducting studies to derive reference intervals (RIs), various statistical procedures are commonly applied at each step, from the planning stages to final computation of RIs. Determination of the necessary sample size is an important consideration, and evaluation of at least 400 individuals in each subgroup has been recommended to establish reliable common RIs in multicenter studies. Multiple regression analysis allows identification of the most important factors contributing to variation in test results, while accounting for possible confounding relationships among these factors. Of the various approaches proposed for judging the necessity of partitioning reference values, nested analysis of variance (ANOVA) is the likely method of choice owing to its ability to handle multiple groups and being able to adjust for multiple factors. Box-Cox power transformation often has been used to transform data to a Gaussian distribution for parametric computation of RIs. However, this transformation occasionally fails. Therefore, the non-parametric method based on determination of the 2.5 and 97.5 percentiles following sorting of the data, has been recommended for general use. The performance of the Box-Cox transformation can be improved by introducing an additional parameter representing the origin of transformation. In simulations, the confidence intervals (CIs) of reference limits (RLs) calculated by the parametric method were narrower than those calculated by the non-parametric approach. However, the margin of difference was rather small owing to additional variability in parametrically-determined RLs introduced by estimation of parameters for the Box-Cox transformation. The parametric calculation method may have an advantage over the non-parametric method in allowing identification and exclusion of extreme values during RI computation. Clin Chem Lab Med 2010;48:1537-51.