两种方法计算σ值评价生化检测项目分析性能的比较

Comparison between two methods in calculatingσvalues for evaluating analytical performance of biochemical assay item

目的分别利用室间质评(EQA)数据和全球室内质控(IQC)数据计算生化分析仪部分检测项目的偏倚(Bias),比较两种方法计算的σ值的差异。方法利用公式σ=(TEa%-Bias%)/CV%计算实验室24个生化检测项目两个不同水平的σ值。式中TEa为允许总误差,采用中华人民共和国卫生行业标准(WS/T403-2012)和国家卫生健康委员会临床检验中心EQA标准;变异系数(CV)是利用IQC数据获得的,表示不精密度;Bias采用两种方法计算得到,一种利用EQA数据,一种利用全球IQC数据,从而得到两种方法计算的σ值。结果对于由EQA数据计算出的σ值,两个水平的σ值均高于6的有8个项目,占所有项目的33.3%,两个水平的σ值均高于3的有19个项目,占所有项目的79.2%。对于由全球IQC数据计算出的σ值,两个水平的σ值均高于6的有10个项目,占所有项目的41.7%,两个水平的σ值均高于3的有22个项目,占所有项目的91.7%。除Cl、Na和CRE的水平2以及LDH的水平1和水平2外,其余项目由全球IQC数据计算得到的σ值均高于由EQA结果计算得到的σ值。结论利用σ方法进行分析性能评价时选择不同的数据可能会得到不同的结果。实验室在改进分析质量的过程中需多次对σ水平进行评价。

Objective To calculate the bias of partial detection items in the biochemical analytical instruments by respectively using the external quality assessment(EQA)data and the global internal quality control(IQC)data,and to compare the difference ofσvalues detected by the two methods.Methods The formulaσ=(TEa%-Bias%)/CV%was used to calculate the two different levels ofσvalues in 24 biochemical assay items.In this formula,TEa was the total allowable error.The Health Industry Standard of the People′s Republic of China(WS/T403-2012)and the EQA standard of Clinical Laboratory Center of National Health Commission were adopted;coefficient of variation(CV)was the imprecision and obtained by using the IQC data;Bias was calculated by using the two methods,which were the EQA data and global IQC data,thus theσvalues calculated by the two methods were obtained.Results For theσvalue calculated by the EQA data,there were 8 items of two levels>6,accounting for 33.3%of all items,there were 19 items of the two levels>3,accounting for 79.2%of all items.For theσvalue calculated by using the global IQC data,there were 10 items of two levels>6,accounting for 41.7%of all items,there were 22 items of two levels>3,accounting for 91.7%of all items.Except for the Level 2 of Cl,Na and CRE,Level 1 and Level 2 of LDH,theσvalues calculated by the global IQC data in other items were higher than those calculated by the EQA data.Conclusion Selecting different data may obtain different results when conducting the analytical performance evaluation by using theσmetric.In the process of improving the analytical quality,the laboratory needs to evaluate theσvalues for many times.