临床检验前和检验后阶段的管理

临床实验室长期致力于检验质量,已使其产生错误发生率的西格玛水平为4~5,其超过大多数其他医疗领域。然而,对检验前及检验后阶段错误率的更深的理解及他们对患者潜在的伤害已导致加强对实验室的要求,要求实验室对其直接控制之外的活动承担更大的责任。认可机构有对检验外阶段有效管理的相关要求。有各种免费在线资源可用来帮助管理检验外阶段,国际临床化学及检验医学联合会实验室差错和患者安全工作组最近发表的质量指标和提出性能水平提供了特别有用的基准数据。通过建立在现有的质量管理经验、定量的科学背景及对信息技术的精通,临床实验室适合在实验室范围外在减少差错和提高患者安全方面发挥更大的作用。     

临床检验后阶段质量指标及其质量规范

目的 探讨我国当前检验后阶段的质量指标及其质量规范,为临床实验室建立QI体系提供参考。 方法 采用卫生部临床检验中心和北京科临易检信息技术有限公司共同设计开发的网络平台,向参加中心2015年全国临床检验专业质量指标调查的所有实验室发放调查表按照不同专业和不同医院等级进行分组,采用Kolmogorov-Smirnov检验判断数据正态性,Kruskal-Wallis检验和Mann-Whitney检验分别进行多组和两组间的比较。结果 分别有5 229家、4 643家和4 421家实验室上报了检验报告不正确率、危急值通报率和危急值通报及时率的相关数据。各指标均有超过95%的实验室、σ水平≥3 σ和≥6 σ的实验室则分别占47.87%、91.17%、85.95%。各指标在不同专业之间存在显著差异;除危急值通报率以外,其余2项指标在不同等级医院之间也存在显著差异。结论 我国临床实验室检验后阶段3项QI的差错率相对较低,多数实验室危急值通报率和危急值通报及时率达到了100%。临床实验室应基于此调查,进一步监测3项指标,同时正确有效地识别检验后阶段的薄弱环节,建立更多合适的QI并基于当前技术水平确定相应的质量规范。     

山西省15项临床检验质量指标调查结果与分析

目的 调查分析山西省临床检验15项质量指标现状。方法 利用网络平台,向辖区内598家医疗机构临床实验室发放调查表。对规定时间内回报的数据,利用Microsoft Excel 2003、SPSS13.0进行统计学分析处理。结果 194家实验室回报结果。13项以率统计的指标再用西格玛（Sigma,σ）度量评价,有10项总体σ满足最低可接受水平（3σ）,其余3项总体σ水平均<1。不同等级医院实验室和不同专业之间部分项目有显著差异。不同专业常规检验前周转时间约为30 min,急诊检验为10 min。不同专业常规检验中周转时间在 30~180 min,急诊在 20~60 min。结论 通过本次调查研究了解到检验中的质量控制工作相对薄弱。实验室应加强信息系统建设,保证可靠的数据采集和常态化的监控工作。     

用微机检验昆虫空间分布型的拟合优度

<正> 频次法是分析昆虫空间分布型的经典方法,但其计算过程比较复杂,若用手工计算,不但需要花费大量时间,而且容易出现差错。如果用微机来进行这项工作,则可避免这些不足。这里介绍一个计算机程序。它能对输入的数据作泊松分布(poisson distribution)、奈曼分布(neyman distribution)和负二项式分布(nega-tive binomial distribution)的拟合优度检验。该程序使用简便,只需将数据(可以是原始调查数据,也可以是经过整理的数据)输入计算     

通过ISO 15189认可实验室质量指标制定及监测情况调查

目的 了解目前我国通过ISO 15189认可的实验室质量指标制定及监测情况。 方法 设计质量指标制定及监测情况调查表并下发给185家认可实验室,要求在10月31日前以邮件形式回报结果,使用Microsoft Excel 2010软件进行统计分析。 结果 共85家（占45.95%）实验室回报结果,76家临床实验室,9家独立实验室。不同认可实验室制定的质量指标数量及分布差异较大。76家临床实验室共设置质量指标1105项,每家实验室平均14.5项。9家独立实验室设置质量指标195项,每家实验室平均21.7项。临床实验室制定了更多的检验前、检验中质量指标,独立实验室在设置质量指标时还包括了较多的检验后、支持性过程和其他质量指标。 结论 目前我国认可实验室质量指标制定及监测情况尚不理想。在推进质量指标一致化的同时,实验室应加强宣贯与教育,建议一套完整、科学和实用的质量指标体系。

     

胰酶处理后甲醛固定组织中狂犬病毒抗原的免疫荧光染色

<正>免疫荧光染色(IF)为狂犬病毒诊断,最正确的显微镜检验。但是为了保证结果可靠,检验用的中枢神经系统(CNS)组织,必需用冷藏、冰冻,或者放入50％甘油生理盐水混合液中保存。把组织转运到狂犬病实验室经常出现困难,常因冰箱有限,即使有冰或干冰的隔热包装,但运输中的廷误,常在途中组织已变质,因而增加了假阳性结果的可能。     

临床实验室检验差错的测量研究

实验室对患者安全有重大的影响,因为所有诊断的80~90%是基于实验室检验作出的。据报道,实验室差错发生率为所有试验结果的0.012-0.6%。患者安全是一个管理问题,其可通过实施积极的系统来识别及监控质量故障得到提高。这可通过包括事件报告随后的根本原因分析的反应方法得到促进。这可导致识别及纠正该系统中方针及程序的不足之处。另一种方法是前瞻性方法,如失效模式和效应分析(或故障模式和影响分析)。本文的重点是整个检验过程,预测主要不良事件以及先发制人防止它们的发生。它可用于高风险过程的前瞻性的风险分析以减少实验室及其他患者医疗领域内出差错的可能性。     

第10届国际生物奥林匹克竞赛(1999)实验试题(一)

第 1实验室 :微生物学实验试题说明　　在实验考试部分中要检验你所了解的生物学基本方法、程序和技术 ,并展示你能利用这些知识达到实验目的。这将在以下 4个不同的实验中进行检验。第 1实验室 :微生物学第 2实验室 :遗传学和组织学第 3实验室 :形态学和生理学第 4实验室 :行为学每个实验考试 70 min,每个实验的分数是 2 6～ 50分 ,实验总分 1 50分。如果你在答题中选择了错误的答案和正确的答案 ,则你该题的得分将比你仅选了正确答案的得分要低。在这个实验室中有两组不同的作业 ,首先 ,你要检查你面前两个广口瓶 (广口瓶 1和 2 )的内含物…     

医院实验室生物安全管理模式与策略

目的 探索适合我国医院的实验室生物安全管理模式和策略。方法和结果 通过比较医院实验室与科研院所实验室的不同特点,分析目前医院实验室安全管理的模式和管理内容所存在的问题和隐患;论述医院生物安全管理的范围和管理重点,讨论可行的实验室安全管理模式和策略。结论 医院的实验室生物安全管理与科研院所不同,要与临床医疗工作统筹兼顾,临床检验实验室和科研实验室有不同的管理内容和环节。     

我国临床实验室开展医护人员满意度调查现状分析

目的 了解我国临床实验室开展顾客满意度调查的现状。方法 向定期参加卫生部临床检验中心（室间质评计划的2 299家综合性医院的临床实验室发放网络调查表，收集顾客满意度调查开展情况的相关信息。使用Pearson相关分析和K-W检验分析组间差异。结果 调查表回报率是34.54%，其中92.19%的实验室进行过满意度调查。Pearson相关分析和K-W检验结果显示，不同等级医院临床实验室的调查百分率和调查频率存在差异。结论 我国临床实验室对顾客满意度的概念和涵意不甚了解，应该进行更多的临床实验室顾客满意度的研究。     

Decentralization of Acid Fast Bacilli(AFB) External Quality Assurance Using Blind Rechecking for Sputum Smear Microscopy in Ethiopia

Introduction

Ethiopia achieved a rapid expansion of TB microscopic centers for acid fast bacilli (AFB). However, external quality assurance (EQA) services were, until recently, limited to few regional and sub-regional laboratories. In this paper, we describe the decentralization experience and the result of EQA using random blinded rechecking.

Materials and Methods

The routine EQA quarterly report was compiled and analyzed. A positive result by the microscopic center while the EQA center reported negative result is categorized as false positive (FP). A negative result by the microscopic center while the EQA center reported positive is considered false negative (FN). The reading of EQA centers was considered a gold standard to compute the sensitivity, specificity, positive predictive (PPV) and negative predictive values (NPV) of the readings of microscopic centers.

Results

We decentralized sputum smear AFB EQA from 4 Regional Laboratories (RRLs) to 82 EQA centers and enrolled 956 health facilities in EQA schemes. Enrollment of HFs in EQA was gradual because it required training and mentoring laboratory professionals, institutionalizing internal QA measures, equipping all HFs to perform diagnosis, and establishing more EQA centers. From 2012 to 2014 (Phase I), the FP rate declined from 0.6% to 0.2% and FN fell from as high as 7.6% to 1.6% in supported health facilities (HFs). In HFs that joined in Phase II, FN rates ranged from 5.6 to 7.3%. The proportion of HFs without errors has increased from 77.9% to 90.5% in Phase I HFs and from 82.9% to 86.9% in Phase II HFs. Overall sensitivity and specificity were 95.0% and 99.7%, respectively. PPV and NPV were 93.3% and 99.7%, respectively.

Conclusion

Decentralizing blinded rechecking of sputum smear microscopy is feasible in low-income settings. While a comprehensive laboratory improvement strategy enhanced the quality of microscopy, laboratory professionals’ capacity in slide reading and smear quality requires continued support.     

Quality assessment of measurement

Assessing the quality of measurements is of interest to organizers of external quality assessment schemes (EQAS, or proficiency testing schemes), laboratory analysts and managers, users of laboratory results and other agencies. Scheme organizers run test programmes, define standards of acceptable and non-acceptable performance, and interact with participants and oversight authorities. Laboratory personnel are responsible for the quality management system and to choose whether to accept the standards set by scheme organizers or to adopt their own. Users receive and act upon the laboratory results.Schemes within the same analytical sector are often organized very differently causing contradictory assessment of performance. The Network of EQAS in occupational and environmental laboratory medicine established collaborative projects designed to enhance assessment of measurement quality and to improve the reliability of laboratory results.To address the issue of variations in assessing the quality of measurements, and in response to comments from some participants, standards derived from biological variation, rather than on the analytical performance of participants have been developed. Evaluation of test materials with respect to homogeneity and stability, and work on methods to give the assigned value to test materials, has also been undertaken. Following from these projects, further collaboration is planned which will provide better quality assessment of measurement to scheme participants and their users.     

Impact of standardization on clinical cell analysis by flow cytometry

The evolution of flow cytometry from a research tool to a pivotal technology for clinical diagnostic purposes has required significant efforts to standardize methods. The great advantage of flow cytometry is that it's applications are highly amenable to standardization. Here, we review the efforts that have been made for flow cytometric applications in four major fields of clinical cell analysis: CD4+ T-cell enumeration, CD34+ hematopoietic stem and progenitor cell enumeration, screening for the HLA-B27 antigen and leukemia/lymphoma immunophenotyping. These standardization efforts have been parallelled by the establishment of external quality assessment (EQA) schemes in many countries worldwide. The goal of these EQA exercises has been primarily educa-tional, but their results will increasingly serve as a basis for laboratory accreditation. This important development requires that the EQA schemes, in particular the quality of the distributed samples and the procedures for evaluating the results, meet the highest standards.     

External Quality Assessment of Reading and Interpretation of Malaria Rapid Diagnostic Tests among 1849 End-Users in the Democratic Republic of the Congo through Short Message Service (SMS)

Background

Although malaria rapid diagnostic tests (RDT) are simple to perform, they remain subject to errors, mainly related to the post-analytical phase. We organized the first large scale SMS based external quality assessment (EQA) on correct reading and interpretation of photographs of a three-band malaria RDT among laboratory health workers in the Democratic Republic of the Congo (DR Congo).

Methods and Findings

High resolution EQA photographs of 10 RDT results together with a questionnaire were distributed to health facilities in 9 out of 11 provinces in DR Congo. Each laboratory health worker answered the EQA by Short Message Service (SMS). Filled-in questionnaires from each health facility were sent back to Kinshasa. A total of 1849 laboratory health workers in 1014 health facilities participated. Most frequent errors in RDT reading were i) failure to recognize invalid (13.2–32.5% ) or negative test results (9.8–12.8%), (ii) overlooking faint test lines (4.1–31.2%) and (iii) incorrect identification of the malaria species (12.1–17.4%). No uniform strategy for diagnosis of malaria at the health facility was present. Stock outs of RDTs occurred frequently. Half of the health facilities had not received an RDT training. Only two thirds used the RDT recommended by the National Malaria Control Program. Performance of RDT reading was positively associated with training and the technical level of health facility. Facilities with RDT positivity rates >50% and located in Eastern DR Congo performed worse.

Conclusions

Our study confirmed that errors in reading and interpretation of malaria RDTs are widespread and highlighted the problem of stock outs of RDTs. Adequate training of end-users in the application of malaria RDTs associated with regular EQAs is recommended.     

Quality assurance in cervical cancer screening

Objectives. to examine the effectiveness of introducing External Quality Assessment (EQA) into all laboratories which undertake gynaecological cytopathology. to assess pathologists and cytotechnologists regularly for their competence to screen cervical smears, regardless of their standing in the laboratory hierarchy or their experience of gynaecological cytopathology.
Methods. Each participant was asked to screen and report on 10 slides during a 2 h period. the assessment was carried out by a facilitator under the direction of a specially appointed EQA Committee. A maximum score of 20 points was awarded for a completely correct set of answers. A minus score was awarded for a missed abnormal smear. Seventeen pathology laboratories in North West Thames Regional Health Authority participated; 146 cytologists were assessed.
Results. A pilot and four rounds of EQA have been completed and a total 5350 smears examined. Out of 2568 dyskaryotic (abnormal) smears screened, 0.7% were not identified correctly. of the 146 cytologists taking part in the assessment, 95% achieved a score of 17 or more. Three participants were identified who did not reach an acceptable level of competence and appropriate remedial action was taken.
Conclusion. the EQA scheme detected unacceptable levels of performance which can be quickly rectified. Participation of 100% has been maintained on a voluntary basis, and 4 years experience of the scheme confirms that a very high standard of screening prevails in the Region. the study illustrates that voluntary self-regulation is acceptable in the NHS, and the introduction of similar EQA schemes on a national scale will go a long way to establishing confidence in the cervical cancer screening programme.     

Where did I take that snapshot? Scene-based homing by image matching

In homing tasks, the goal is often not marked by visible objects but must be inferred from the spatial relation to the visual cues in the surrounding scene. The exact computation of the goal direction would require knowledge about the distances to visible landmarks, information, which is not directly available to passive vision systems. However, if prior assumptions about typical distance distributions are used, a snapshot taken at the goal suffices to compute the goal direction from the current view. We show that most existing approaches to scene-based homing implicitly assume an isotropic landmark distribution. As an alternative, we propose a homing scheme that uses parameterized displacement fields. These are obtained from an approximation that incorporates prior knowledge about perspective distortions of the visual environment. A mathematical analysis proves that both approximations do not prevent the schemes from approaching the goal with arbitrary accuracy, but lead to different errors in the computed goal direction. Mobile robot experiments are used to test the theoretical predictions and to demonstrate the practical feasibility of the new approach. Received: 11 December 1997 / Accepted in revised form: 12 June 1998     

Distinct error rates for reference and nonreference genotypes estimated by pedigree analysis

Errors in genotype calling can have perverse effects on genetic analyses, confounding association studies, and obscuring rare variants. Analyses now routinely incorporate error rates to control for spurious findings. However, reliable estimates of the error rate can be difficult to obtain because of their variance between studies. Most studies also report only a single estimate of the error rate even though genotypes can be miscalled in more than one way. Here, we report a method for estimating the rates at which different types of genotyping errors occur at biallelic loci using pedigree information. Our method identifies potential genotyping errors by exploiting instances where the haplotypic phase has not been faithfully transmitted. The expected frequency of inconsistent phase depends on the combination of genotypes in a pedigree and the probability of miscalling each genotype. We develop a model that uses the differences in these frequencies to estimate rates for different types of genotype error. Simulations show that our method accurately estimates these error rates in a variety of scenarios. We apply this method to a dataset from the whole-genome sequencing of owl monkeys (Aotus nancymaae) in three-generation pedigrees. We find significant differences between estimates for different types of genotyping error, with the most common being homozygous reference sites miscalled as heterozygous and vice versa. The approach we describe is applicable to any set of genotypes where haplotypic phase can reliably be called and should prove useful in helping to control for false discoveries.     

Monitoring standards for molecular genetic testing in the United Kingdom, the Netherlands, and Ireland

Molecular genetic techniques have entered many areas of clinical practice. Public expectations from this technology are understandably high. To maintain confidence in this technology, laboratories must implement the highest standards of quality assurance (QA). External quality assessment (EQA) is recognized as an essential component of QA. The United Kingdom National External Quality Assessment Service (UKNEQAS) for Molecular Genetics, first set up in 1991, is currently the longest provider of EQA to molecular genetic testing laboratories in the UK, The Netherlands, and Ireland. Errors in the scheme are sporadic events. However, evidence from this and other EQA schemes suggests that a residual error rate persists, which should be taken into account in clinical practice. This EQA scheme has evolved from the respective scientific bodies of the constituent countries and retains a strong emphasis on collective peer review. It is essential that the steps taken to ensure quality in this rapidly expanding field are clear and transparent to participants and public alike. We describe the procedures developed and the governance imposed to monitor and improve analytical and reporting standards in participant laboratories and we compare our experiences with those of equivalent EQA services in the United States.     

Development of a technical external quality assurance scheme in non‐gynaecological cytology in UK

Technical external quality assurance (EQA) schemes are well established for histopathology and cervical cytology but, to date, sadly lacking for diagnostic cytology (DC). This timely review redresses the balance by describing the development and evaluation of a technical EQA scheme for DC available to the UK, Europe and beyond.     

A comparison and user-based evaluation of models of textual information structure in the context of cancer risk assessment

Background  

Many practical tasks in biomedicine require accessing specific types of information in scientific literature; e.g. information about the results or conclusions of the study in question. Several schemes have been developed to characterize such information in scientific journal articles. For example, a simple section-based scheme assigns individual sentences in abstracts under sections such as Objective, Methods, Results and Conclusions. Some schemes of textual information structure have proved useful for biomedical text mining (BIO-TM) tasks (e.g. automatic summarization). However, user-centered evaluation in the context of real-life tasks has been lacking.