Analysis of the analytical performance of laboratories participating in two major U.S. bulk asbestos proficiency testing programs

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.     

Performance of asbestos fiber counting laboratories in the NIOSH proficiency analytical testing (PAT) program

Asbestos fiber counting data reported in the NIOSH Proficiency Analytical Testing (PAT) Program are used in this study to evaluate the analytical performance of participating laboratories and to determine if overall performance has improved during a ten-year period. PAT laboratories have achieved intralaboratory precision of 0.18 to 0.28 relative standard deviation (RSD), and interlaboratory precision of 0.33 to 0.44 RSD. In addition, there was higher variability between PAT laboratories from 1974 to 1978, when the program underwent considerable change and growth than the variability found during previous or subsequent time periods. The improvements in interlaboratory precision by approximately one-third since 1974 and the tendency of laboratories with little PAT experience to have poorer interlaboratory precision than more experienced laboratories raises a concern that interlaboratory precision may deteriorate as large numbers of new laboratories start to enroll in the PAT Program with the increased emphasis on asbestos removal in public buildings.     

Performance of laboratories analysing welding fume on filter samples: results from the WASP proficiency testing scheme

This paper emphasizes the need for occupational hygiene professionals to require evidence of the quality of welding fume data from analytical laboratories. The measurement of metals in welding fume using atomic spectrometric techniques is a complex analysis often requiring specialist digestion procedures. The results from a trial programme testing the proficiency of laboratories in the Workplace Analysis Scheme for Proficiency (WASP) to measure potentially harmful metals in several different types of welding fume showed that most laboratories underestimated the mass of analyte on the filters. The average recovery was 70-80% of the target value and >20% of reported recoveries for some of the more difficult welding fume matrices were <50%. This level of under-reporting has significant implications for any health or hygiene studies of the exposure of welders to toxic metals for the types of fumes included in this study. Good laboratories' performance measuring spiked WASP filter samples containing soluble metal salts did not guarantee good performance when measuring the more complex welding fume trial filter samples. Consistent rather than erratic error predominated, suggesting that the main analytical factor contributing to the differences between the target values and results was the effectiveness of the sample preparation procedures used by participating laboratories. It is concluded that, with practice and regular participation in WASP, performance can improve over time.     

Antimicrobial proficiency testing of National Nosocomial Infections Surveillance System hospital laboratories.

OBJECTIVE: The National Nosocomial Infections Surveillance (NNIS) System personnel report trends in antimicrobial-resistant pathogens. To validate select antimicrobial susceptibility testing results and to identify test methods that tend to produce errors, we conducted proficiency testing among NNIS System hospital laboratories. SETTING: NNIS System hospital laboratories in the United States. METHODS: Each laboratory received five organisms (ie, an imipenem-resistant Serratia marcescens, an oxacillin-resistant Staphylococcus aureus, a vancomycin-resistant Enterococcus faecalis, a vancomycin-intermediate Staphylococcus epidermidis, and an extended-spectrum beta-lactamase (ESbetaL)-producing Klebsiella pneumoniae). Testing results were compared with reference testing results from the Centers for Disease Control and Prevention. RESULTS: Of 138 laboratories testing imipenem against the Serratia marcescens strain, 110 (80%) correctly reported minimum inhibitory concentrations (MICs) or zone sizes in the resistant range. All 193 participating laboratories correctly reported the Staphylococcus aureus strain as oxacillin resistant Of the 193 laboratories, 169 (88%) reported correct MICs or zone sizes for the vancomycin-resistant Enterococcus faecalis. One hundred sixty-two (84%) of 193 laboratories demonstrated the ability to detect a vancomycin-intermediate strain of Staphylococcus epidermidis, however, disk diffusion performed poorly when testing both staphylococci and enterococci with vancomycin. Although laboratory personnel correctly reported nonsusceptible extended-spectrum cephalosporins and aztreonam results for K. pneumoniae, only 98 (51%) of 193 correctly reported this organism as an ESbetaL producer. CONCLUSION: Overall, NNIS System hospital laboratory personnel detected most emerging resistance patterns. Disk diffusion continues to be unreliable for vancomycin testing of staphylococci and must be used cautiously for enterococci. Further education on the processing of ESbetaL-producing organisms is warranted.     

浙江省水质中砷汞检测能力验证计划结果分析

目的:为了提高实验室检测结果的准确性与可比性,以及检验机构的整体能力,识别实验室间存在的差异。方法:采用国际通用的稳健统计用"Z比分数"的统计方法对水中砷、汞的检测结果进行分析。结果:此次质控样品共发放至全省各相关的检验机构中心共189家实验室,其中砷检测结果满意的有137家,满意率为78.7%;汞检测结果满意的有100家,满意率为76.9%。结论:全省检验机构的汞、砷总体检测能力较高,部分实验室技术质量水平有待提高。     

Lessons learned for the assessment of children's pesticide exposure: critical sampling and analytical issues for future studies

In this article we examine sampling strategies and analytical methods used in a series of recent studies of children's exposure to pesticides that may prove useful in the design and implementation of the National Children's Study. We focus primarily on the experiences of four of the National Institute of Environmental Health Sciences/U.S. Environmental Protection Agency/ Children's Centers and include University of Washington studies that predated these centers. These studies have measured maternal exposures, perinatal exposures, infant and toddler exposures, and exposure among young children through biologic monitoring, personal sampling, and environmental monitoring. Biologic monitoring appears to be the best available method for assessment of children's exposure to pesticides, with some limitations. It is likely that a combination of biomarkers, environmental measurements, and questionnaires will be needed after careful consideration of the specific hypotheses posed by investigators and the limitations of each exposure metric. The value of environmental measurements, such as surface and toy wipes and indoor air or house dust samples, deserves further investigation. Emphasis on personal rather than environmental sampling in conjunction with urine or blood sampling is likely to be most effective at classifying exposure. For infants and young children, ease of urine collection (possible for extended periods of time) may make these samples the best available approach to capturing exposure variability of nonpersistent pesticides; additional validation studies are needed. Saliva measurements of pesticides, if feasible, would overcome the limitations of urinary metabolite-based exposure analysis. Global positioning system technology appears promising in the delineation of children's time-location patterns.     

检测实验室检测结果的质量保证初探

作为第三方为客户提供检测数据的检测实验室,数据的准确性关系到检测机构本身的检测水平、在客户中的权威性,更涉及到检测结果的公正性,影响到执法机关的执法效力等。因此,及早开展并完善质量保证活动,对树立检测机构自身的权威,开拓服务市场,为客户提供优质的服务非常重要。本文举例的A实验室,自2004年3月正式启动实验室国家认可和计量认证评审的准备工作开始,经过1年多的时间,从文件制定到逐步建立并完善质量管理体系,有效提高检测水平,于2005年9月顺利通过了实验室认可和计量认证“二合一”的现场评审。现结合实际案例和多年工作的体会,…     

参加美国病理家学会抗磷脂抗体能力验证活动效果分析

目的汇总分析北京协和医院风湿免疫科实验室和全世界参加美国病理家学会(College of American Pathologists,CAP)抗磷脂抗体(antiphospholipid antibodies, aPLs)项目的能力验证(proficiency testing,PT)活动8年的效果,以不断提高监控实验室检测aPLs项目的能力和质量。 方法采用回顾性分析研究。北京协和医院风湿免疫科实验室自2009年1月至2016年12月,每年以邮件方式接收2批,每批3份检测样本,在10 d内采用酶联免疫吸附试验(enzyme-linked immununosorbent assay, ELISA)完成抗心磷脂抗体(anticardiolipin,aCL)、抗β2糖蛋白1抗体(anti-β2- glycoprotein 1,aβ2GP1)检测,并将结果回报CAP。 结果本实验室自2009年1月起至2016年12月止,参加CAP的aPLs项目PT活动16次,共96个检测结果,所有结果均为可接受,总PT成绩为100%。8年期间,全世界参加CAP的aPLs项目PT活动的实验室数量逐年增加,2009年第1次PT与2016年第2次PT相比,参加aCL-IgG PT活动的实验室数量增长了24.55%,参加aCL-IgM PT活动的实验室数量增长了24.53%,参加aCL-IgA PT活动的实验室数量增长了20.13%,参加aβ2GP1-IgG PT活动的实验室数量增长了179.73%,参加aβ2GP1-IgM PT活动的实验室数量增长了197.01%,参加aβ2GP1-IgA PT活动的实验室数量增长了151.16%。检测方法逐渐由单一的ELISA变为多种方法学,包括ELISA法、化学发光法、荧光酶免疫分析法和液态芯片技术。全世界的回报结果显示,高滴度阳性和阴性样本检测结果的一致性较好,均高于90%,而低、中等滴度阳性样本检测结果的一致性较差。 结论本实验室的aPLs项目检测结果达到了CAP的能力验证质量要求。全世界越来越多的实验室重视参与aPLs项目的室间质量评价活动,但弱阳性、中等强度阳性的aPLs样本的检测质量仍有待提高。     

The network of the Italian laboratories: a proficiency test on the quantification of trace elements in serum

A proficiency test on the quantification of Al, Cu, Mn, Se and Zn in serum was carried out to verify the performance of about 30 regional laboratories of the network of Italian laboratories. The exercise consisted of four runs in which the laboratories were free in choosing analytical methods to determine trace elements in freeze-dried animal serum. Laboratories performances were evaluated by the study of statistical functions as Coefficients of Variation (CV), Youden plot and Z-score value. As for Al, the results were generally characterized by good accuracy and precision, in spite of the low levels of the element (5-7 microg l(-1)). Copper determination had some problems only at low concentration (about 160 microg l(-1)--first run), in which an elevated number of anomalous data were found. Better data were achieved for Zn, for which anomalous values were mainly stragglers than outliers. Due to the low number of data for Mn (concentrations from 0.6 to 60 microg l(-1)) and Se (concentration from 45 to 106 microg l(-1)), a restricted statistical treatment was applied; for these elements high CV values were found (range from 30 to 80%). The results of this trial confirmed that participation in a proficiency test represents a benefit for all analytical laboratories. In fact, with few exceptions, most of the participants improved their performances in terms of Z-score values.     

Comparison of laboratory performance with blind and mail-distributed proficiency testing samples.

Simulated addict urine samples containing drugs were sent to collaborating hospital administrators and officials of methadone centers, who then forwarded the samples to their supporting laboratories as though they were ordinary specimens from patients. The laboratories, which were already participating in the proficiency testing program of the Center for Disease Control, received the identical test samples in the mail as part of a regular Center for Disease Control proficiency testing program. Most of the laboratories performed acceptably with the mail-distributed samples, but many performed poorly when the identical samples were sent to them as if they were specimens from patients. Because of the limitations of proficiency testing involving mail-distribution samples and the impracticality of extensive testing with blind samples on a national level, the Center for Disease Control proposes to compliment its regular proficiency testing program with a monitored, onsite program of performance evaluation.     

Review of respirator performance testing in the workplace: issues and concerns.

Performance capability of respirators has traditionally been evaluated by testing components of the respirator (e.g., filter efficiency), facepiece fit, total inward leakage, or some other measure of performance evaluated under laboratory conditions. In recent years, increased emphasis has been placed on development of test methods suitable for evaluating respirator performance in the workplace. The goal of such testing is to evaluate the level of protection provided by respirators in the work environment. The AIHA Respiratory Protection Committee believes that workplace testing of respirators has the potential to be an excellent tool for increasing knowledge about the effectiveness of respiratory protection. However, a number of technical issues remain to be addressed before optimal test protocols and data analysis methods can be defined. The progress made to date in workplace testing will be reviewed, and broader discussion about key elements that must be considered when developing guidelines for testing respirators in the workplace will be initiated.     

Study design and hypothesis testing: issues in the evaluation of evidence from research in nutritional epidemiology.

In addressing questions about the relations of dietary factors to disease in human populations, epidemiologic studies must account for the complexity of dietary habits, the intercorrelations among dietary habits, and the correlations of those habits with other behaviors. Furthermore, for studies of chronic disease, relevant dietary exposures may occur over decades. The classic epidemiologic study designs have been used to examine the associations between diet and disease; the strengths and weaknesses of those designs must be considered. Concerns have been raised regarding the validity of the measures of diet, the differential recall of diet by diseased individuals in case-control studies, and confounding by other related factors in both case-control and cohort studies. In clinical trials there may be difficulties in effecting the necessary dietary changes, especially for macronutrients, and there are also concerns about those circumstances in which participants cannot be blinded to their treatment. For case-control and cohort studies and for some clinical trials, intercorrelations among nutrients are a concern in the identification of factors that are important in the etiology of disease. It is important to understand these considerations when interpreting nutritional epidemiologic studies for the purpose of setting public policy. No one study can be considered definitive in the understanding of a diet-disease relation. However, epidemiologic findings from multiple studies taken together can contribute significantly to our understanding of diet in relation to disease in humans.     

白酒中邻苯二甲酸二乙酯类测定的能力验证过程控制与结果分析

目的通过对参加白酒中邻苯二甲酸二乙酯类,包括邻苯二甲酸二丁酯(DBP)、邻苯二甲酸二(2-乙基已酯)(DEHP)能力验证活动的结果进行分析,提高实验室检验检测能力,保证检验检测结果准确。方法依据《食品安全国家标准食品中邻苯二甲酸二乙酯的测定》(GB 5009.271-2016)及《白酒中邻苯二甲酸酯类的测定能力验证作业指导书》(ACAS-PT820)的要求,对样品进行处理并检测,能力验证组织单位采用Z值评定对实验室结果进行统计分析并判定。结果经评定样品19-N400中DBP、DEHP Z值分别是-0.4、-3.4,DBP结果满意,DEHP结果判定离群;样品19-P961中DBP、DEHP Z值分别是-0.9、-1.2,结果均为满意。经原因分析整改,补测DEHP结果满意。结论从能力验证中发现的问题着手,分析检验检测全过程各环节影响因素,制定整改措施,改进检验检测方法。通过参加能力验证活动,提高了检验检测能力水平,有效保障检测数据的准确性。     

Laboratory testing of whole cell pertussis vaccine: a WHO proficiency study using the Kendrick test.

Whole cell pertussis vaccine (WCV), commonly in combination with vaccines for diphtheria and tetanus, has an important role in reducing morbidity and mortality among children in most parts of the world. Testing to assure the efficacy of such vaccines is essential. We have, therefore, carried out, under the Global Training Network (GTN) of the Department of Vaccines and Biologicals at the World Health Organization (WHO), a proficiency study involving 13 laboratories in 12 countries that routinely test WCV. Two vaccine samples were tested in this study and represented samples which were expected clearly either to pass (sample B, a full strength vaccine) or to fail (sample A, 1/8 strength of vaccine B). Data from this study showed good performance by the majority of participants. Most assays were statistically valid and were carried out to the level of precision achieved for these assays in previous studies. This study also indicated that, relative to the assay precision, the in-house reference (IHR) preparations are in general accurately calibrated. Statistically valid assays of the sub-potent vaccine, A, showed it to fail in all except one laboratory. Statistically valid assays of the potent vaccine, B, showed it to pass in all laboratories. Nevertheless, the between laboratory variability of estimates for vaccine B, and for comparisons of the two vaccine samples suggested that there are some differences in results in different laboratories. The introduction of a common working standard may assist in reducing inter-laboratory variation. This study has shown clearly satisfactory performance by most laboratories. However, a serious problem was detected in one laboratory where the sub-potent vaccine A could have been passed and was not distinguished from the eight-fold more potent vaccine B. There were also indications of possible problems in several other laboratories, where IHR preparation may not be accurately calibrated or where vaccine samples A and B may not be completely distinguished. Although this study provides reassurance that most laboratories perform well, it demonstrates the essential role of ongoing proficiency studies in high-lighting problems.     

Moving towards universal health insurance in China: performance, issues and lessons from Thailand

China is now in the course of implementing a new round of health system reforms. Universal health insurance coverage through the basic social medical insurance system is high on the reform agenda. This paper examines the performance of China's current social medical insurance system in terms of revenue collection, risk pooling, the benefit package, and provider payment mechanisms based on a literature review and publicly available data. On the basis of critical assessment, the paper attempts to address the issues challenging China as it moves towards universal coverage. Focusing in particular on the reform experience in Thailand as it implemented universal coverage, the following policy implications for further reform in China are articulated, taking into account China's particular circumstances: firstly, the gaps in the benefit package across different schemes should be further reduced; secondly, the prevailing fee-for-service payment system needs to be transformed; thirdly, the primary health care delivery and referral system needs to be strengthened in coordination with the reform of the health insurance system; and fourthly, raising the risk pooling level and integrating fragmented insurance schemes should be long-run objectives of reform.     

血清中尿酸及尿素测定能力验证研究

目的:评价参与能力验证(PT)实验室的血清中尿酸和尿素测定能力,以提升检测水平.方法:选取14个省(自治区)、直辖市的16家医疗器械检验所、食品药品检验机构、疾病控制中心、质量监督检测研究院及其他科研单位的实验室,按照中国合格评定国家认可委员会(CNAS)的相关文件要求,对实验室全部样本中的真正PT样本进行稳定性和均匀...     

Development of rice reference material and its use for evaluation of analytical performance of food analysis laboratories

Data quality is one of the major concerns in development of food composition database and to editors of many peer-reviewed journals in accepting a scientific paper for publication. Regular use of a reference material and participation in a proficiency testing programme could improve the reliability of the analytical data. The objectives of this project were to prepare rice test material with assigned values and to use it to assess the analytical performance of laboratories which are involved in research and analysis of rice. The international guidelines, ISO Guide 35, ISO 13528 and ISO Guide 43, were followed as much as possible throughout the preparation of the reference material and the laboratory performance study. Brown rice (Jasmine variety) was ground to particle size which passed completely through a sieve with pore size 250 μm and packed in laminated aluminum foil bags under vacuum. Based on the analyses of representative nutrients – moisture, protein, iron, zinc and vitamin B1 – the samples were demonstrated homogeneous. Ten expert laboratories from various countries, 36 laboratories from Thailand, and 16 laboratories from ASEAN and Asia registered for the laboratory performance study. The samples were sent for analysis of selected proximate composition (moisture, protein, dietary fibre and ash), two minerals (iron, zinc), and one labile nutrient (vitamin B1) using routine analytical methods. The assigned values of the nutrients in the test materials, as robust mean ± robust SD or predicted SD, were established with their uncertainties. For proximate composition, 67–87% of participating laboratories showed good analytical performance. However, many of them showed questionable and unsatisfactory performance on the analyses of dietary fibre (55%) and vitamin B1 (47%). The evaluation of the results of moisture, protein and iron with their uncertainties against the assigned values of the test material using En score was also demonstrated. Finally, the consensus values of nutrients in the rice sample as mean ± SD were developed from the analytical results of laboratories with good performance for both within- and between-laboratories. This test material can be used as a reference material for internal and external quality control systems to improve the quality of the analytical data.     

北京地区医疗机构临床输血实验室检测能力调查与分析

目的 调查北京医疗机构临床输血实验室检测能力的基本情况,为行政管理部门制定相关管理政策提供技术依据.方法 由北京市临床输血质量控制和改进中心指派检查专家携带质控品对输血实验室进行现场检查,记录输血从业人员在检测前、中、后的技术操作过程以及应用的仪器设备、检测试剂及检测结果等信息进行统计与分析.结果 本次现场检查比室间质评的合格率低,部分实验室不能在规定时间内完成对质控品的检测;实际操作与本实验室制定的质量文件不一致;55.9％的一级医院和25.6％二级医院仪器、设备设施、流程布局无法满足临床输血工作需要;部分技术人员缺乏专业知识和基本技能的培训,应对急诊能力差,单独分析问题能力不强;检测过程记录和结果填写欠规范.结论 北京地区医疗机构临床输血实验室检测能力总体水平不高,应加强改进和提高.