应用六西格玛理论评价强生vitros5．1干化学生化分析仪系统性能和设计室内质控方案

The application of 6 σ theory in assessment of the internal quality control scheme in the performance and design in Johnson Vitros 5.1 dry biochemical analyzer system

目的应用六西格玛（6σ）理论对强生vitros5．1干化学生化分析系统检测项目的性能进行量化，并设计各项目的室内质控方案，探讨6σ理论在临床质量管理中的价值。方法根据σ=[允许总误差（TEa）-偏倚（Bias）]／变异系数（CV），计算K、Na、Cl、GLU、Ur、Cr、CHE、LIPA共8个检测项目的σ水平。TEa取2018年卫生部临床检验中心（NCCL）室间质量评价的评价标准，Bias以本室参加NCCL室间质量评价的平均偏倚计算所得，以2016年2月至2017年2月期间质控品日间不精密度作为变异系数（CV）。根据Westgard西格玛规则，制定个性化的室内质量控制方案。对于性能未达到6σ的项目，计算其质量目标指数（QGI=Bias／1．5CV），确立性能改进方案。结果8个检测项目的总性能σ水平为2．21～14．01。CHE、LIPA〉6σ；3σ〈K、NA、GLU、Cr〈6σ；Cl、Ur〈3σ；分析性能未达到6σ的项目中，Na、Ur、cr的QGI〈0．8，需要优先改进精密度，K、Cl、GLU的QGI介于0．8-1．2之间，需要同时改进精密度和准确度；CL和Ur未达到3σ，提示存在较严重的质量缺陷，急需采取质量改进措施。根据σ值对每个项目进行了个性化的质控方案设计。结论6σ理论可直观地评价强生vitros5．1干化学生化分析系统的性能，设计个性化的室内质量控制方案和指导质量持续改进。

Objective To quantify the items of Johnson Vitros 5.1 dry biochemistry analysis system using 6 σ theory, and design the internal quality control （IQC） of each item, and explore the value of 6 σ theory in clinical quality management. Methods We calculated the a levels of 8 items of Potassium, Sodium, Chlorine, Glucose, Urea, Creatinine, Cholinesterase, and Lipase in a equation of σ=[the total error （TEa） - bias] / coefficient of variation （CV）. TEa was based on the external quality assessment （EQA） of National Center for Clinical Laboratory （NCCL） in 2018, with an average bias of the EQA by NCCL, and with a CV of daily imprecision from February 2016 to February 2017. According to the Westgard a rule , a personalized IQC scheme was developed. For items whose performance was not up to 6 a, the quality target index （QGI=Bias/1.5CV） was calculated and the modified scheme was established. Results The a level of total performance of the 8 items was from 2.21 to 14.01. Among them, Cholinesterase and Lipase were above 6 σ, and Potassium, Sodium, Glucose and Creatinine were more than 3 σ and less than 6 σ, while Chlorine and Urea were less than 3 σ. For items in which the performance did not reach 6 σ, when the QGI of Sodium, Urea, and Creatinine were less than 0.8, it needed to be improved in precision. When the QGI of Potassium, Chlorine, and Glucose were 0.8-1.2, it needed to be improved in both precision and accuracy. When Chlorine and Urea did not reach to 3 σ, this suggested that there were serious quality defects, for which it needed to be improved in quality improvement measures. According to the value of σ each item of the quality control was designed individually. Conclusions The 6 σ theory can directly evaluate the performance of Johnson Vitros 5.1 dry chemical biochemistry analysis system. To design personalized IQC scheme is to guide a continuous quality improvement.