2014年全国血铅检验项目实验室内不精密度现状分析

Analysis of the imprecision of internal quality control of blood lead level testing in China,2014

目的调查全国血铅(blood lead level,BLL)检测实验室的室内质量控制的精密度现状,并与原卫生部发布的相关文件所给出的要求进行比较,提出改进措施。方法采用基于Web方式的室间质量评价(external quality assessment,EQA)软件系统,采用2014年参加全国血铅室间质量评价计划的实验室的室内质量控制数据,包括当月(2014年2月)和累积的变异系数,使用的方法、仪器以及其他室内质量控制相关信息等。使用Microsoft Excel 2007和SPSS 13.0对数据进行分析,根据原卫生部发布的《血铅临床检验技术规范》,计算血铅项目的室内质量控制变异系数的通过率,并且比较不同浓度水平和不同检测系统间的通过率是否存在差异,使用χ2检验,双侧α=0.05为检验水准。结果共427家单位回报了有效结果。其中120家实验室还上报了第二个批号的室内质控数据。浓度范围在20~100μg/L时,当月通过率为88.07%,累计通过率为88.82%;≥100μg/L时,当月通过率为85.26%,累计通过率为81.78%。目前我国血铅检测主要为A、B、C三个检测系统,除系统A累积变异系数外,同一检测系统不同分析结果浓度范围的通过率差异无统计学意义(P>0.05)。不同检测系统间当月和累积的变异系数,在不同分析结果浓度中的通过率均差异无统计学意义(P>0.05)。结论血铅检测项目实验室内精密度水平直接关系着检验结果的质量水平。通过对当月和累积的室内质量控制数据的变异系数的监测,并将室内质量控制数据计算的变异系数与相关要求进行比较,可以评价该检测系统的不精密度水平是否满足规定的质量要求,为实验室间结果的可比性检验提供精密度的信息。

Objective To discuss the coefficient of variations （CV） of internal quality control in blood lead level measurement, and compare with the technical specification of the relative documents issued by the Ministry of Health. Methods Data had been collected by web-based submission system from laboratories enrolled in 2014 blood lead level external quality assessment （EQA） program, which included the CV of February of 2014 and long-term cumulative data, method, instrument and other information. Microsoft Excel 2007 and SPSS 13.0 were used to analyze the data. The acceptable rate of CV of different concentration was calculated accord- ing to the ＂Technical specification of blood lead level measurement＂ issued by the Ministry of Health in 2006. Chi-square test was used to compare the acceptable rate of CV. Results Four hundred and twenty-seven laboratories reported effective results and 120 reported CV of two lots of internal quality control data. The overall acceptable rate in the concentration of 20 to 100 μg/L were 88.07% in February and 88.82% of cumulative rate, while they were 85.26% and 81.78% in the concentration of 100μg/L and above. There were three major measuring systems of blood lead level testing in China, A, B and C. There was no significant difference of the acceptable rate of CV under different concentrations of each measurement system （P^O. 05）, except for the cumulative CV of system A. Also, the differences of the acceptable rates of CV under different measuring systems were not significant （P）O. 05）. Conclusions It is an effective method for clinical labora- tories to improve test quality by monitoring the current and cumulative CVs of internal quality control and by comparing with proper evaluation criteria to determine if the analysis system can meet specific quality require- ments or technical specification.