Carey R Neill, Cembrowski George S, Garber Carl C, Zaki Zohreh
The Peninsula Regional Medical Center, Salisbury, MD 21801-5493, USA.
Arch Pathol Lab Med. 2005 Aug;129(8):997-1003. doi: 10.5858/2005-129-997-PCOSRF.
Proficiency testing (PT) participants can interpret their results to detect errors even when their performance is acceptable according to the limits set by the PT provider.
To determine which rules for interpreting PT data provide optimal performance for PT with 5 samples per event.
We used Monte Carlo computer simulation techniques to study the performance of several rules, relating their error detection capabilities to (1) the analytic quality of the method, (2) the probability of failing PT, and (3) the ratio of the peer group SD to the mean intralaboratory SD. Analytic quality is indicated by the ratio of the PT allowable error to the intralaboratory SD. Failure of PT was defined (Clinical Laboratory Improvement Amendments of 1988) as an event when 2 or more results out of 5 exceeded acceptable limits. We investigated rules with limits based on the SD index, the mean SD index, and percentages of allowable error.
No single rule performs optimally across the range of method quality.
We recommend further investigation when PT data cause rejection by any of the following 3 rules: any result exceeds 75% of allowable error, the difference between any 2 results exceeds 4 times the peer group SD, or the mean SD index of all 5 results exceeds 1.5. As method quality increases from marginal to high, false rejections range from 16% to nearly zero, and the probability of detecting a shift equal to 2 times the intralaboratory SD ranges from 94% to 69%.
能力验证（PT）参与者即使其表现根据PT提供者设定的限值是可接受的，也可以解释其结果以检测误差。
确定哪些解释PT数据的规则能为每次事件包含5个样本的PT提供最佳性能。
我们使用蒙特卡洛计算机模拟技术来研究几种规则的性能，将它们的误差检测能力与（1）方法的分析质量、（2）PT失败的概率、（3）同组标准差与实验室内标准差均值的比值相关联。分析质量由PT允许误差与实验室内标准差的比值表示。PT失败（根据1988年《临床实验室改进修正案》）定义为5个结果中有2个或更多结果超出可接受限值的情况。我们研究了基于标准差指数、平均标准差指数和允许误差百分比的限值规则。
在方法质量的整个范围内，没有单一规则能表现最佳。
当PT数据因以下3条规则中的任何一条而被拒绝时，我们建议进一步调查：任何结果超过允许误差的75%、任何两个结果之间的差异超过同组标准差的4倍、或所有5个结果的平均标准差指数超过1.5。随着方法质量从边缘提高到高质量，错误拒绝率从16%降至几乎为零，检测到等于实验室内标准差2倍的偏移的概率从94%降至69%。
