医学实验室血清K^+、Na^+、Cl^-测量不确定度评估及检测质量改进分析

Measurement uncertainties for the determinations of serum K^+,Na^+ and Cl^- and their quality improvement

目的评估医学实验室离子选择电极(ISE)法检测血清钾离子(K^+)、钠离子(Na^+)和氯离子(Cl^-)的测量不确定度(MU),提高检测质量。方法参考中国合格评定国家认可委员会(CNAS)2012年发布的《医学实验室——测量不确定度的评定与表达》,采用"自上而下"方法,联合室内质量控制(IQC)和室间质量评价(EQA)数据评估K^+、Na^+、Cl^-的相对扩展不确定度(U_(rel)),对2个主要分量[U_(crel)(bias)和U_(rel)(Rw)]分别设定管理目标,将未达标项作为提高检测质量的重点。结果当K^+水平在3.64~4.41和5.70~7.00 mmol/L时,其MU分别为8.84%和7.76%,U_(crel)(bias)未达标,U_(rel)(Rw)达标,ISE法检测K^+的正确度性能需改进;当Na^+水平在106~122和130~152 mmol/L时,其MU分别为5.20%和4.60%,U_(crel)(bias)和U_(rel)(Rw)均未达标,ISE法检测Na^+的正确度和精密度性能均需提高;当Cl^-水平在68.9~78.3和96.4~107.9 mmol/L时,其MU分别为7.15%和6.86%,U_(crel)(bias)和U_(rel)(Rw)均未达标,ISE法检测Cl^-的正确度和精密度性能均需提高。结论在医学实验室检测质量的管理工作中,参照CNAS文件,联合IQC和EQA数据评估并分析MU及其主要分量,能够明确具体检测性能的不足,以采取有针对性的改进措施,从而进一步提高检测质量。

Objective To evaluate the measurement uncertainties(MU)for the determinations of serum potassium ion(K+),sodium ion(Na+)and chlorinum ion(Cl-)by ion selective electrode(ISE),and to improve the quality.Methods According to the Medical Laboratory-Evaluation and Expression of Uncertainty of Measurement published by China National Accreditation Service for Conformity Assessment(CNAS)in2012,the relative expanded uncertainties(Urel)of serum K+,Na+and Cl-were assessed by"top-down"method with the data of internal quality control(IQC)and external quality assessment(EQA).The2main components[bias Ucrel(bias)and reproducibility Urel(Rw)]were set as goals.When the Ucrel(bias)or Urel(Rw)was beyond the goals,the accuracy or precision should be improved further.Results When the levels of K+were3.64-4.41and5.70-7.00mmol/L,the MU were8.84%and7.76%,respectively,the Ucrel(bias)were beyond the goals,the Urel(Rw)were not beyond the goals,and the accuracy should be improved.When the levels of Na+were106-122and130-152mmol/L,the MU were5.20%and4.60%,the Ucrel(bias)and Urel(Rw)were beyond the goals,and the accuracy and precision should be improved.When the levels of Cl-were68.9-78.3and96.4-107.9mmol/L,the MU were7.15%and6.86%,the Ucrel(bias)and Urel(Rw)were beyond the goals,and the accuracy and precision should be improved.Conclusions In the management of determination quality,the insufficiency of determination could be found by analyzing MU and2main components which are assessed with the data of IQC and EQA and CNAS technical reports,which can be improved further.