目的:通过实施实验室间比对项目,对全国各省市疾病预防控制中心实验室饮用水中镉的检测能力进行分析评价。
方法:在实验室间比对项目中,以二级标准材料的制备方法作为样品制备的参考。采用单因素方差分析(ANOVA)、线性回归和均值一致性检验(t检验)对模拟运输样品的均匀性、稳定性和短期稳定性进行检验。在使用核密度估计测试实验室测试结果分布的基础上,采用精密度统计学方法对实验室检测结果进行分析,采用Z评分对各参与实验室的检测能力进行评价。
结果:全国共有409个实验室参加了能力测试计划。参与实验室的383个实验室(93.6%),取得了满意的结果。结果由4个实验室(1.0%)提供,他们的能力可疑。最后,参与实验室总数中有22个实验室(5.4%),结果被发现是异常值。
结论:实验室间比对项目统计结果表明,饮用水中镉的检测能力在全国各省市疾病预防控制中心的实验室中排名令人满意,少数实验室的测试能力需要进一步提高。
OBJECTIVE: To analyze and evaluate the testing capability of cadmium in drinking water in the laboratories of the provincial and municipal centers for disease control and prevention across the country by implementing the interlaboratory comparison project.
METHODS: The preparation method of the secondary standard materials were used as the reference for the sample preparation in the interlaboratory comparison project. The homogeneity and stability of the samples and short-term stability for simulated transportation were tested by single factor analysis of variance(ANOVA) and linear regression and mean consistency test(t test). On top of using the kernel density estimation to test the distribution of laboratory test result, we adopted precision statistical method to analyze the laboratory test result and used Z-score to evaluate the testing ability of each participating laboratory.
RESULTS: A total of 409 laboratories throughout the country participated in the proficiency testing program.383 laboratories(93.6%) of participating laboratories, obtained satisfactory result. Results provided by 4 laboratories(1.0%) of total participating laboratories, were found suspicious in their capacities. Finally, there were 22 laboratories(5.4%) of total participating laboratories, with result found to be outliers.
CONCLUSIONS: The statistical result of the interlaboratory comparison project show that the testing capability of cadmium in drinking water has been ranked as satisfactory in the laboratories of the provincial and municipal centers for disease control and prevention across the country, and the testing capability of a small number of laboratories requires further improvement.