Klee G G, Tholen D W
Division of Laboratory Medicine, Mayo Clinic, Rochester, MN 55905.
Arch Pathol Lab Med. 1988 Apr;112(4):399-403.
A nonparametric analysis method that does not depend on gaussian data distributions is proposed for evaluation of proficiency survey results. The proposed method also provides a mechanism for processing results qualitatively reported as "less than" or "greater than" pre-established limits of quantitation. The evaluation limits for acceptability are calculated to include the central 95% of all test results from all methods. Systematic differences in the levels of analyte concentrations caused by differences in analytical measurement systems are normalized by mathematically transforming the test results from each analytic method by dividing them by their method-specific group median. This nonparametric method was compared with the traditional mean +/- 2 SD limits using data collected for digoxin, free thyroxine, and quantitative chorionic gonadotropin measurement in the College of American Pathologists Ligand Assay Survey. The nonparametric method more accurately classified 5% of the results as "unacceptable." When more than 2.5% of the test results for a method were designated as "less than," no lower limit was used for evaluation and only 2.5% of results were classified as "unacceptably high." The current College of American Pathologists procedure favors analytical methods with larger coefficients of variation by setting wider limits of acceptability, while the proposed procedure favors methods with smaller coefficients of variation.
本文提出了一种不依赖高斯数据分布的非参数分析方法，用于评估能力验证调查结果。该方法还提供了一种机制，用于处理定性报告为“低于”或“高于”预先设定的定量限的结果。可接受性的评估限计算为包括所有方法的所有测试结果的中心95%。通过将每种分析方法的测试结果除以其特定方法组中位数进行数学变换，对分析测量系统差异导致的分析物浓度水平的系统差异进行归一化。使用美国病理学家学会配体分析调查中收集的地高辛、游离甲状腺素和定量绒毛膜促性腺激素测量数据，将这种非参数方法与传统的均值±2标准差限进行了比较。非参数方法更准确地将5%的结果分类为“不可接受”。当一种方法超过2.5%的测试结果被指定为“低于”时，不使用下限进行评估，只有2.5%的结果被分类为“高得不可接受”。美国病理学家学会目前的程序通过设定更宽的可接受限，有利于变异系数较大的分析方法，而本文提出的程序则有利于变异系数较小的方法。
