Harvey Bruce W, Winstead Wayne G
Microanalytical Sciences Department, Science and Engineering Group, RTI International, Research Triangle Park, North Carolina 27709-2194, USA.
J Occup Environ Hyg. 2008 Jul;5(7):455-62. doi: 10.1080/15459620802138197.
Quality assurance and proficiency testing programs have been available for 27 years for U.S. laboratories using polarized light microscopy to analyze bulk building materials for asbestos. Total enrollment in the two principal bulk asbestos proficiency testing programs conducted by RTI International peaked at nearly 900 laboratories in the mid-1990s. Enrollment has stabilized in the last 5 years at approximately 475 laboratories, and rates of return of analysis results currently exceed 95%. More than 115,000 test samples have been sent worldwide by RTI to laboratories in these two programs. A review of more than 109,000 analysis results was undertaken to determine the frequencies of various qualitative error types, the types of bulk building materials most responsible for those errors, and the accuracy of precision of semiquantitative results. This assessment revealed that a small number of bulk building materials cause the majority of difficulties in each program, although error frequencies vary between the two programs. Overall laboratory performance has improved since the programs first began in the late 1980s, with a significant decline in qualitative errors and a much less dramatic decrease in errors associated with semiquantitative estimation of the amount of asbestos present.
对于美国使用偏振光显微镜分析散装建筑材料中的石棉的实验室而言，质量保证和能力验证计划已经实施了27年。rti国际公司开展的两项主要的散装石棉能力验证计划的参与实验室总数在20世纪90年代中期达到近900家的峰值。在过去5年中，参与实验室数量稳定在约475家，目前分析结果的返回率超过95%。rti已向全球各地的实验室发送了超过11.5万个测试样品，用于这两项计划。对超过10.9万份分析结果进行了审查，以确定各种定性误差类型的频率、导致这些误差的主要散装建筑材料类型以及半定量结果的精度准确性。该评估表明，虽然两个计划中的误差频率有所不同，但少数散装建筑材料在每个计划中都造成了大部分困难。自20世纪80年代末这些计划首次启动以来，实验室的整体表现有所改善，定性误差显著下降，与石棉含量半定量估计相关的误差下降幅度则小得多。
