Westgard J O, Falk H, Groth T
Clin Chem. 1979 Mar;25(3):394-400.
A computer-stimulation study has been performed to determine how the performance characteristics of quality-control rules are affected by the presence of a between-run component of variation, the choice of control limits (calculated from within-run vs. total standard deviations), and the shape of the error distribution. When a between-run standard deviation (Sb) exists and control limits are calculated from the total standard deviation (St, which includes Sb as well as the within-run standard deviation, Sw), there is generally a loss in ability to detect analytical disturbances or errors. With control limits calculated from Sw, there is generally an increase in the level of false rejections. The presence of non-gaussian error distribution appears to have considerably less effect. It can be recommended that random error be controlled by use of a chi-square or range-control rule, with control limits calculated from Sw. Optimal control of systematic errors is difficult when Sb exists. An effort should be made to reduce Sb, and this will lead to increased ability to detect analytical errors. When Sb is tolerated or accepted as part of the baseline state of operation for the analytical method, then further increases in the number of control observations will be necessary to achieve a given probability for error detection.
已进行了一项计算机模拟研究，以确定质量控制规则的性能特征如何受到批间变异成分的存在、控制限的选择（根据批内标准差与总标准差计算）以及误差分布形状的影响。当存在批间标准差（Sb）且控制限根据总标准差（St，包括Sb以及批内标准差Sw）计算时，检测分析干扰或误差的能力通常会下降。当控制限根据Sw计算时，假拒收水平通常会增加。非高斯误差分布的存在似乎影响要小得多。建议通过使用卡方或极差控制规则来控制随机误差，控制限根据Sw计算。当存在Sb时，对系统误差进行最佳控制很困难。应努力降低Sb，这将提高检测分析误差的能力。当Sb被容忍或作为分析方法操作基线状态的一部分被接受时，那么为了达到给定的误差检测概率，有必要进一步增加控制观察次数。
