[Analysis of inter-laboratory comparison results of arsenic in urine and explore the influence factors on detection].

Objective: Through inter-laboratory comparison to analysis and evaluation of the detection capacity of arsenic in the urine. Methods: Urine arsenic samples were prepared with normal human urine as matrix. The homogeneity of the samples was investigated and the results were statistically analyzed by single factor analysis of variance. 2 samples were issued to each participant laboratory. A robust statistical four-point distance method was used to calculate the results submitted by each participant laboratory and the test capability of the laboratory was assessed by the z-score method. By means of method experiments and records, the reasons of dissatisfaction and the influencing factors of the results were discussed. Results: The statistic of the homogeneity of urine arsenic samples was less than the critical value (P>0.05) , which showed that the arsenic in the sample was homogeneous. The satisfactory rate of comparison between 36 laboratories was 86.1%. The main reasons for dissatisfaction were the testing conditions and the quality control measures. The selection of sample pretreatment, acidity control and hydrogenation conditions was the main influencing factor for the determination of urinary arsenic by atomic fluorescence spectrometry. Conclusion: The level of urinary arsenic detection in the occupational health laboratories was generally better and a few laboratories need to be improved ability of detection. It was very important to control the test conditions reasonably and strengthen the quality control measures to improve the accuracy of urine arsenic detection.目的： 通过实验室间比对，对职业健康检查和职业病诊断机构实验室尿中砷的检测能力进行分析和评价。 方法： 以正常人尿为基质，参照一级标准物质技术规范制备尿砷比对样品，对样品进行均匀性考察并采用单因素方差分析法统计结果；向每个参加实验室发放2份样品，采用稳健统计四分位距法统计各参加实验室提交的结果，并通过Z比分数法评定实验室检测能力；通过查看各参加实验室提交的报告及记录及方法实验，探讨结果不满意原因和检测影响因素。 结果： 尿砷样品均匀性考察的统计量F小于临界值（P>0.05），显示样品中的砷是均匀的；36家实验室比对结果满意率为86.1%；结果不满意的主要原因在于检测条件控制和质控措施；样品预处理、酸度控制及氢化物发生条件的选择是原子荧光光谱法测定尿砷的主要影响因素。 结论： 职业健康检查和职业病诊断机构实验室尿中砷检测水平总体较好，少部分实验室的检测能力有待提高；合理控制检测条件、加强质量控制措施对提高尿砷检测结果的准确性尤为重要。.