Bio-Rad Laboratories, Quality Systems Division, Plano, TX 75074, USA.
Clin Chem. 2012 May;58(5):925-9. doi: 10.1373/clinchem.2011.181818. Epub 2012 Feb 22.
Repeating a QC that is outside 2SD from the mean (1:2s rule) appears to be a common practice. Although this form of repeat sampling is frowned on by many, the comparative power of the approach has not been formally evaluated.
We computed power functions mathematically and by computer simulation for 4 different 1:2s repeat-sampling strategies, as well as the 1:2s rule, the 1:3s rule, and 2 common QC multirules.
The false-rejection rates for the repeat-sampling strategies were similarly low to those of the 1:3s QC rule. The error detection rates for the repeat-sampling strategies approached those of the 1:2s QC rule for moderate to large out-of-control error conditions. In most cases, the power of the repeat-sampling strategies was superior to the power of the QC multirules we evaluated. The increase in QC utilization rate ranged from 4% to 13% for the repeat-sampling strategies investigated.
The repeat-sampling strategies provide an effective tactic to take advantage of the desirable properties of both the 1:2s and 1:3s QC rules. Additionally, the power of the repeat-sampling strategies compares favorably with the power of 2 common QC multirules. These improvements come with a modest increase in the average number of controls tested.
重复均值 2SD 以外的 QC（1:2s 规则）似乎是一种常见做法。尽管许多人对这种重复抽样形式持反对态度，但该方法的比较效能尚未得到正式评估。
我们通过数学计算和计算机模拟，针对 4 种不同的 1:2s 重复采样策略、1:3s 规则、1:2s 规则和 2 种常见的 QC 多规则，计算了效能函数。
重复采样策略的错误拒绝率与 1:3s QC 规则相似。对于中等至较大的失控误差情况，重复采样策略的误差检测率接近 1:2s QC 规则。在大多数情况下，重复采样策略的效能优于我们评估的 QC 多规则。重复采样策略的 QC 利用率提高了 4%至 13%。
重复采样策略提供了一种有效的策略，可以充分利用 1:2s 和 1:3s QC 规则的理想特性。此外，重复采样策略的效能与 2 种常见 QC 多规则的效能相当。这些改进是以平均测试的控制数量略有增加为代价的。
