2014年全国452家实验室全血铜、锌、钙、镁、铁检验项目实验室内不精密度分析

Analysis of the Imprecision of Internal Quality Control of 452 Laboratories Testing Copper, Zinc, Calcium, Magnesium and Iron in Whole Blood of Children in China

目的调查全血五元素（铜、锌、钙、镁、铁）室内质量控制的精密度现状，并与目前所确定的生物学变异（此处作为室内质量控制精密度的评价标准）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，收集2014年参加全国全血五元素检验室间质量评价计划的实验室的室内质量控制数据，为2014年2月份的452家实验室，包括当月的和累积的室内质量控制变异系数，所使用的方法、仪器等信息，其他室内质量控制相关信息等。使用Microsoft Excel2007和SPSS13．0对数据进行分析。根据生物学变异导出最佳、适当和最低允许不精密度的评价标准，计算这5个项目的室内质量控制变异系数的通过率。全血五元素铜、锌、钙、镁、铁的生物学变异，适当、最低和最佳标准分别为铜2．50％，3．68％和1．23％；锌4．70％，6．98％和2．33％；钙1．00％，1．43％和0．48％；镁1．80％，2．70％和0．90％；铁13．30％，19．88％和6．63％。结果377-382家实验室有效的上报了批号1的室内质控数据，96家实验室上报了批号2。达到适当质量规范的变异系数比例范围：批号1（2014年2月），1．85％（钙）-95．5％（铁）；批号2（2014年2月），3．13％（钙）-96．88％（铁）；批号1（累积），2．82％（钙）-96．06％（铁）；批号2（累积），1．10％（钙）-98．90％（铁）。各批号内不同质量规范的各检验项目阀不精密度的通过率差异均有统计学显著性意义（P〈0．01）。目前有A，B，C三个检测系统，除铜当月不精密度适当和最低标准，锌当月和累积不精密度的适当和最低标准，钙累积不精密度最低标准和铁累积不精密度最佳标准外，其余项目和标准各检测系统间均差异无统计学显著性意义（P〉0．05）。结论通过对当月和累积的室内质控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。对于全血五元素项目来说，除了铁外，目前使用基于生物学变异的质量规范来评价不精密度水平还是过于严格了。

Objective To investigate the coefficient of variations （CV） of internal quality control （IQC） of five elements （copper, zinc, calcium, magnesium, and iron） of whole blood in children testing, and compare with the quality specification derived from biological variations. Methods Data had been collected by web-based submission system, the laboratories which en- rolled in 2014 five elements of whole blood in children external quality assessment （EQA） program had attended. The data was included：the CV of February of 2014 and long-term cumulative data,method and instrument, etc. Microsoft Excel 2007 and SPSS 13.0 had been used to analyze the data. The optimum,desirable and minimum performance of quality specification of allowable imprecision had been derived from biological variations, 1.23 %, 2.50 % and 3.68 % for copper, 2.33% ,4.70 and 6.98% for zinc,0.48%,1.00% and 1.43% for calcium,0.90%,1.80% and 2.70% for magnesium, 6.63%,13.30% and 19.88% for iron,respectively. Results 377-382 laboratories reported effective results,96 of them reported CV of two lots of IQC material. The range of acceptable rate of CV meeting desirable quality specification was：lot 1 （February）, 1.85 % （calcium） to 95.5% （iron）;lot 2 （February）,3.13% （calcium） to 96.88% （iron）;lot 1 （cumulative）,2.82% （calcium） to 96.06% （iron） ;lot 2 （cumulative） ,1.10% （calcium） to 98.90% （iron）. There was signifieant difference between analytes in the acceptable rate of CV of each lot of IQC material for every quality specification（P〈0.01）. The mainstream of meas- urement systems of five elements of whole blood in children testing in China were A, B and C. There was no significant difference of the acceptable rate of CV between different measurement systems for all quality specification （P〉0.05）, except the February CV of copper and zinc, cumulative CV of zinc for desirable and minimum quality specification, cumulative CV of calcium for minimum quality specification,and cumulative CV of iron for optimum quality specification. Conclusion It is an effective method for clinical laboratories to improve test quality by monitoring the current and cumulative CV of IQC and comparing them against proper evaluation criteria to evaluate if the analysis system can meet specific quality requirements or technical specification. For the five elements of whole blood, the quality specification derived from biological variation was too strict to be used in the quality assessment for clinical laboratories in China.