Ehrmeyer S S, Laessig R H
School of Allied Health Professions, Medical Technology Program, University of Wisconsin-Madison 53706.
Clin Chem. 1987 Oct;33(10):1901-2.
Currently, proficiency-testing (PT) programs are expanding the use of fixed limits to evaluate interlaboratory performance. These limits are an attempt to relate total allowable intralaboratory analytical error and performance in a PT program. Fixed limits are a means of counteracting the effects of overly stringent performance requirements derived from the interlaboratory group mean and standard deviations (SD) achieved by today's very precise analytical systems. Our previously described computer model of a PT program is used to delineate the quantitative relationship between the magnitude of intralaboratory coefficient of variation (CV) and bias that is compatible with fixed interlaboratory limits of 5, 10, 15, and 20% relative error. However, fixed limits alone do not fully characterize intralaboratory performance. The efficiency, or the percentage of times a laboratory's PT results are required to fall within the fixed limit, also must be considered when criteria for PT performance are being set. For example, a 10% fixed limit and a 80% efficiency will allow laboratories having CV-bias combinations from 8%-0%, 7%-4%, etc., to pass PT. The use of a 95% efficiency will allow CV-bias combinations from 4.8%-0%, 3.5%-4%, etc., to pass PT. We give a figure that depicts all possible combinations for four fixed limits and six efficiencies.
目前，能力验证（PT）计划正在扩大使用固定限值来评估实验室间的性能。这些限值旨在关联实验室内部总允许分析误差与PT计划中的性能。固定限值是一种应对因当今非常精确的分析系统所达到的实验室间组均值和标准差（SD）而产生的过于严格的性能要求影响的手段。我们之前描述的PT计划计算机模型用于描绘实验室内部变异系数（CV）大小与偏差之间的定量关系，该关系与5%、10%、15%和20%相对误差的固定实验室间限值兼容。然而，仅固定限值并不能完全表征实验室内部性能。在设定PT性能标准时，还必须考虑效率，即实验室PT结果落在固定限值内的次数百分比。例如，10%的固定限值和80%的效率将允许CV - 偏差组合为8% - 0%、7% - 4%等的实验室通过PT。使用95%的效率将允许CV - 偏差组合为4.8% - 0%、3.5% - 4%等的实验室通过PT。我们给出了一个图表，描绘了四个固定限值和六种效率的所有可能组合。
