原子吸收法测定全血中铅浓度的测量不确定度评定

Measurement uncertainty of whole blood lead levels by atomic absorption spectrometry

目的：评定原子吸收法测定全血中铅浓度的测量不确定度，寻找实验室中简便易行的测量不确定度评定方法。方法收集襄阳市中心医院医学检验部2011年1～6月室内质控数据和2011年卫生部临床检验中心2次室间质评结果，依据“自上而下”的方法评定钨舟原子吸收法测定全血中铅浓度的不确定度。结果原子吸收法测定全血铅浓度时的实验室内测量结果复现性引入的测量不确定度为6．2％；偏移引入的相对测量不确定度为5．55％；相对合成标准不确定度为8．29％；犽＝2，包含概率（P）＝95．45％时，相对扩展不确定度为16．58％；当血铅浓度为200．0μg/L时，扩展不确定度为33．2μg/L，全血中铅浓度的不确定度报告为（200．0±33．2）μg/L。结论采用＂自上而下＂的方法能方便地评定原子吸收法测定全血铅浓度的测量不确定度，也适用于实验室中参加了室间质评并进行了合适的室内质控的其他定量测定项目的测量不确定度评定。

Objective To look for simple laboratory method to decide measurement uncertainty. Methods Internal quality con- trol data from January 2011 to June 2011 of Xiangyang city center Hospital Medical Examination Division, and 2 EQA results of 2011 from Clinical Laboratory Center were collected. These uncertainty data were from tungsten boat atomic absorption spectrome- try measured on whole blood lead concentration. Results Atomic absorption spectrometry obtained reproducibility of measurement uncertainty of 6.2 %, offset relative measurement uncertainty by 5.55 % and the relative combined standard uncertainty of 8.29 %, take k= 2, contains the probability P=95.45 %, the relative expanded uncertainty of 16.58 %, when blood lead concentration was 200.0 μg/L, the expanded uncertainty was 33.2 μg/L, the concentration of lead in whole blood uncertainty is reported as （200.0 ±33.2）μg/L. Conclusion A ＂top down＂ approach can easily assess whole blood lead concentration measurement uncertainty,and it suits for the EQA participating laboratories and make the appropriate internal quality control of the other quantitative determination of measurement uncertainty projects.