Cumulative sum procedure in evaluation of EUS-guided FNA cytology: the learning curve and diagnostic performance beyond sensitivity and specificity

Background: Using cumulative sum (CUSUM) chart, we address two questions: (i) Over time, how will an EUS‐FNA (endoscopic ultrasound guided fine needle aspiration) service maintain an acceptable non‐diagnostic rate defined as technical failures, unsatisfactory specimens and atypical and suspicious diagnoses? (ii) Over time, how will EUS‐FNA maintain acceptable diagnostic errors (false‐positives plus false‐negative diagnosis)? Methods: The study included all consecutive patients who underwent EUS‐FNA at our institution from July 2000 to October 2003 and were followed up until December 2004. Using a simple spread sheet, we designed CUSUM charts and used them to track trends and assess performance at a preset acceptable rate of 10% and a preset unacceptable rate of 15% for non‐diagnostic rate and diagnostic errors. We assessed all cases collectively and then in groups defined by site, size and cytopathologist. Results: Of 876 patients undergoing EUS‐FNA, 83 (9.5%) had non‐diagnostic results: 43 (51%) of these diagnoses were ‘atypical’, 27(33%) were ‘suspicious for malignancy’, eight (10%) were ‘insufficient material for diagnosis’ and five (6%) were ‘technical failure’. In 585 cases with adequate follow up, there were 26 (6.3%) diagnostic errors: three (0.5%) were false positive and 23 (3.1) were false negative. The overall CUSUM charts for both non‐diagnostic rate and for diagnostic error rate start with a small period of learning then cross to a significantly acceptable level at case numbers 121 and 97 respectively. Our diagnostic performance was better in lymph nodes than in the pancreas and other organs and was not significantly different for lesions ≤25 mm compared with lesion >25 mm in diameter. Performance was better for pathologists with prior experience than for pathologists without experience. Conclusion: In the current climate of proficiency testing, error tracking and competence evaluation, there is a great potential for the use of CUSUM charts to assess procedure failure and error tracking in quality control programs, particularly when a new procedure such as EUS‐FNA is introduced in the laboratory. Additionally, the method can be used to assess trainee competency and to track the proficiency of practicing cytologists.     

基于控制图的医院服务质量持续改进

目的 应用统计过程控制理论分析指导医院服务质量持续改进。方法 联合使用多个控制图方法对医院服务质量评价指标的变化趋势进行监控,及时发现过程中的异常波动,制定针对性措施实施过程改进。结果 找出了影响医院服务质量数据波动的主要原因,制定改进措施,取得了良好的管理效果。结论 控制图可以准确全面反映医院服务质量的总体情况和过程控制情况,根据数据异常分布状态找到潜在的影响服务质量的原因并进行持续改进,是有效的过程管理工具。     

Risk‐adjusted monitoring of time to event in the presence of long‐term survivors

The use of control charts for monitoring schemes in medical context should consider adjustments to incorporate the specific risk for each individual. Some authors propose the use of a risk‐adjusted survival time cumulative sum (RAST CUSUM) control chart to monitor a time‐to‐event outcome, possibly right censored, using conventional survival models, which do not contemplate the possibility of cure of a patient. We propose to extend this approach considering a risk‐adjusted CUSUM chart, based on a cure rate model. We consider a regression model in which the covariates affect the cure fraction. The CUSUM scores are obtained for Weibull and log‐logistic promotion time model to monitor a scale parameter for nonimmune individuals. A simulation study was conducted to evaluate and compare the performance of the proposed chart (RACUF CUSUM) with RAST CUSUM, based on optimal control limits and average run length in different situations. As a result, we note that the RAST CUSUM chart is inappropriate when applied to data with a cure rate, while the proposed RACUF CUSUM chart seems to have similar performance if applied to data without a cure rate. The proposed chart is illustrated with simulated data and with a real data set of patients with heart failure treated at the Heart Institute (InCor), at the University of São Paulo, Brazil.     

Implementation of a Quality Plan (ISO 9002) In a Regional Tissue Bank

Quality control and standardized preservation methods are essential in the field of transplantation. The International Organization for Standardization (ISO) has established a common set of manufacturing, trade and communications standards that are applicable worldwide and that provide the basis of a quality plan for Tissuebreak Banks.The Sectorial Tissue Banking (STB) of the Regional Blood Transfusion Center (RBTC) of Córdoba (Spain) is a non-profit-making tissue bank, established in 1992 to provide tissues for surgical procedures to the hospitals in a regional area. In 1998, the STB as a part of the RBTC embarked upon the path of becoming ISO-certified: after two years of the implementation of the project, STB attained ISO 9002 certification, thus becoming one of the first tissue banks in Europe to achieve this qualification. In this paper we describe the process of becoming ISO-certified, to demonstrate the positive impact that it has had on our entire organization.The assistance of an outside consultant who provided the necessary information for implementing an ISO quality management system was required. The initial improvement was: a well-defined quality manual to address all elements of the ISO 9002 standard, an improved document control system, detailed standard operating procedures (SOPs) and improved employees training processes. A quality committee team and developed quality indicators were created. The internal quality auditing program was established by the selection of employees from a cross-section of the organization, who were trained in internal auditing processes. A formal corrective action system was developed and implemented to facilitate process improvement. The consultant conducted a pre-certification audit, and one month later the certification audit was performed.In conclusion, the implementation of an ISO quality program in the STB has helped our center to establish a control process in the manufacturing of products and services to meet the expectations of our customers, by providing components and services that comply with the national regulatory standards and requirements.     

人降钙素基因相关肽脂质体质量标准的研究

建立完整的人降钙素基因相关肽脂质体(LipohCGRP)药物的质量标准。用家兔球睫膜血管扩张法测定hCGRP的生物学活性;采用RPHPLC、等电聚焦、薄层层析等方法分别测定样品的纯度、等电点和迁移率及脂质体嵌入率的测定,并按照中国生物制品规程的要求完成了甲醇和氯仿等残留物质的分析和动物安全试验。建立了活性测定方法,能准确测定样品中不到1ng的样品活性单位,连续三批样品的各项指标均符合质量标准的要求。建立了脂质体多肽药物的质量标准,并用于质量检定。     

Parametric and non-parametric prediction intervals based phase II control charts for repeated bioassay data

Quality control for repeated bioassay runs can be performed by phase II control charts, well-known from industrial quality control. The value of interest is the potency, of which a single value per run is available. Parametric and non-parametric prediction intervals are described to estimate quality control intervals for future re-test runs. Violations against the normal distribution occur in real data frequently, particularly outliers. The non-parametric prediction intervals are limited to not too small sample sizes in both the historical and future sampling phases. Therefore, robust prediction intervals based on winsorization are proposed. R-functions for all prediction intervals are provided.     

Evaluation of an internal positive control for Cryptosporidium and Giardia testing in water samples

AIMS: An internal positive control for Cryptosporidium and Giardia monitoring was evaluated for use in routine water monitoring quality control. The control, known as ColorSeed C&G (BTF Pty Ltd, Sydney, Australia), is a suspension containing exactly 100 Cryptosporidium oocysts and 100 Giardia cysts that have been modified by attachment of Texas Red to the cell wall, allowing them to be differentiated from unmodified oocysts and cysts. The control enables recovery efficiencies to be determined for every water sample analysed. METHODS AND RESULTS: A total of 494 water samples were seeded with ColorSeed C&G and with unlabelled Cryptosporidium and Giardia and then analysed. Additionally, the robustness of the ColorSeed labelling was challenged with various chemical treatments. Recoveries were significantly lower for the ColorSeed Texas Red labelled Cryptosporidium and Giardia than recoveries of unlabelled Cryptosporidium and Giardia. However, the differences in recoveries were small. On average ColorSeed Cryptosporidium recoveries were 3.3% lower than unlabelled Cryptosporidium, and ColorSeed Giardia recoveries were 4% lower than unlabelled Giardia. CONCLUSIONS: ColorSeed C&G is suitable for use as an internal positive control for routine monitoring of both treated and raw water samples. SIGNIFICANCE AND IMPACT OF THE STUDY: The small differences in recoveries are unlikely to limit the usefulness of ColorSeed C&G as an internal positive control. The ColorSeed labelling was found to be robust after different treatments.     

Analysis and application of NAT in Dongguan blood center more than 10 years

This report reviewed the efficacy of nucleic acid testing (NAT), derived from assaying and measuring data, using a Cobass201 system at the Dongguan blood center from 2008 to 2017. During this period, four blood screening models, each reflecting procedure improvements designed to improve residual risk (RR) assessment were assessed. A total of 716 846 blood donors were screened, detecting 1 395 positive by the mixed pool test, which were finally modified to 900 positive cases, after final detection by the separation-single test: detecting 6 HIV cases, 4 HCV cases and 890 HBV cases with a total positive rate of 1.25%. The lowest result was obtained from the twice administered enzyme-linked immunoassay (ELISA) test,used in conjunction with the single Cobas MPX v2.0 model,with rates of: 1/7 405 for HBV, 1/346 020 for HCV and 1/473 934 for HIV, respectively. NAT positive rate is not affected by different screening models. NAT is a recent detection method which can be used to good effect with ELISA, and is a worth while procedure for promoting blood transfusion safety.     

Retrospective study on performance of constancy check device in Linac beam monitoring using Statistical Process Control

AimTo examine the application of Statistical Process Control (SPC) and Ishikawa diagrams for retrospective evaluation of machine Quality Assurance (QA) performance in radiotherapyBackgroundSPC is a popular method for supplementing the performance of QA techniques in healthcare. This work investigates the applicability of SPC techniques and Ishikawa charts in machine QA.Materials and MethodsSPC has been applied to recommend QA limits on the particular beam parameters using the QUICKCHECK^webline QA portable constancy check device for 6 MV and 10 MV flattened photon beams from the Elekta Versa HD linear accelerator (Linac). Four machine QA parameters – beam flatness, beam symmetry along gun target direction and left-right direction, and beam quality factor (BQF) – were selected for retrospective analysis. Shewhart charts, Exponentially Weighted Moving Average (EWMA) charts and Cumulative Sum (CUSUM) charts were obtained for each parameter. The root causes for a failure in machine QA were broken down into an Ishikawa diagram enabling the user to identify the root cause of error and rectify the problem subsequently.ResultsShewhart charts and EWMA charts applied could detect loss in control in one variable in the 6 MV beams and in all four variables in 10 MV beams. CUSUM charts detected offsets in the readings. The Ishikawa chart exhaustively included the possible errors that lead to loss of control.ConclusionSPC is proven to be effective for detection of loss in control in machine QA. The Ishikawa chart provides the set of probable root causes of machine error useful while troubleshooting.     

流感疫苗中间品-鸡胚尿囊病毒液质量控制的研究

为建立流感疫苗中间品-鸡胚尿囊病毒液质量控制点提供依据。用鲎试剂法、微生物限度检查法、沙门菌检查法检测流感疫苗中间品一鸡胚尿囊病毒液的细菌内毒素含量、微生物限度及沙门菌。在300份鸡胚尿囊病毒液中,细菌内毒素含量大于5EU／mL的阳检率为5％;微生物限度检查中小于lO个／mL细菌菌落数的占78．67％,小于10个／mL霉菌菌落数的占80．67％,小于10个／mL酵母菌菌落数的占88．67％。沙门菌属的阳检率为4％,其中未检出A～F群的沙门菌。对流感疫苗中间品-鸡胚尿囊病毒液进行细菌内毒素,微生物限度及沙门菌检测可避免不合格尿囊病毒液进入后续生产,污染后续中间品。     

上海市医疗质量控制综合评分体系研究

目的 构建一套客观通用的医疗质量综合评分体系,从而加强对各医疗机构总体医疗质量的控制,促进医疗机构质量不断提升,为政府有关部门提供可操作性的政策建议。方法 在文献综述的基础上应用德尔菲法（Delphi Method）对医疗机构质量控制综合评分指标体系的重要性、评估难度以及理想评估次数进行评价,建立评价指标体系。结果 构建的指标体系包含三个层级结构,共32个指标,各级指标的重要性评价意见的协调系数均有统计学意义,专家们较一致的认为管理类别的评价指标评估难度较大,理想的评估频次是一年2次。结论 构建的评价指标体系符合上海市的实际情况,可以应用到实际质量控制综合评价工作中。     

内镜清洗与消毒环节感染因素分析及预防措施研究

目的:总结我院内镜中心清洗与消毒过程中发生感染的主要危险因素,制定相应的预防措施,降低内镜感染发生率,确保患者医疗安全。方法:专人检查内镜清洗消毒全过程,统计各个环节发生感染的危险因素。随机抽取600例消毒后处于备用状态的内镜,采集内镜内腔及外表面标本,检测结果作为评估清洗消毒质量指标。结果:检测600例样本合格584例,合格率97.3%,胃镜、肠镜、十二指肠镜、气管镜和超声内镜合格率分别为98.6%,96.8%,95.6%,96.0%和97.2%;16例不合格样本中共检出病原菌28株,其中幽门杆菌13株,大肠埃希菌7株,铜绿假单胞菌4株,绿脓杆菌2株,金黄色葡萄球菌1株,肺炎克雷伯菌1株;16例检测不合格原因分析中,刷洗不彻底占37.5%,未按说明要求使用多酶及消毒液占18.75%,特殊感染患者用过的内镜未做特殊处理占12.5%,内镜干燥不充分及工作人员手卫生不达标各占6.25%。结论:内镜清洗消毒环节引发感染的危险因素众多,应加强对内镜中心所有人员的感染控制教育,定期对清洗消毒人员进行职业化培训,规范管理清洗消毒流程,建立可追溯性登记系统,从各个环节把关内镜清洗消毒的质量,是预防消化内镜中心发生感染的主要手段。     

Control charts for improved decisions in environmental management: a case study of catchment water supply in south‐west Western Australia

Environmental monitoring is becoming increasingly sophisticated with the widespread adoption of data loggers, sensor arrays and remote sensing, leading to larger scale, higher resolution and superior quality data. However, interpreting monitoring data and deciding when and how to apply environmental management remains a subjective and underdeveloped area of research. Control charts, developed in industrial settings to identify when manufacturing processes were beyond the acceptable bounds of production quality, represent one solution. Despite their potential utility, control charts have rarely been adopted in environmental monitoring. In theory, they are able to identify undesirable trends early and provide transparent and broadly consensual criteria for defining when management action should take place, that is action is triggered when parameter values are observed beyond the agreed control limits of the process. Once triggered, a predetermined management action is implemented. Possible actions are many and varied, and range from investigation and increased monitoring to intervention in the system. Here, the utility of control charts in monitoring water supply in south‐western Australia from 1911 to 2010 is examined, and their ability to provide an early, transparent and easily understandable means of triggering management action is assessed. Two control chart types are applied: the X‐bar chart and the CUSUM chart. X‐bar charts varied widely in their ability to trigger action and were insensitive to many traditional threshold criteria (of which there are many to choose from). In contrast, standard CUSUM charts are specifically designed to detect subtler shifts away from a mean trend and hence provided a more consistent warning of the decline in water supply. While managers were aware of the decline in water supply from an early stage, we believe that control charts could have clearly communicated this earlier, enabling consensus among decision makers to be reached more rapidly.     

肺炎支原体P1重组蛋白的提取纯化及应用研究

提取纯化肺炎支原体(Mycoplasma pneumoniae,Mp)P1重组蛋白,建立酶联免疫吸附实验(ELISA)的方法,协助临床肺炎支原体感染的诊断。以GST融合蛋白层析柱提取、纯化Mp P1重组蛋白做抗原,以全肺炎支原体菌体成分做抗原对照,建立间接ELISA实验方法,检测40份正常献血者血清标本和51份疑似MP感染临床血清标本的IgG抗体。重组蛋白经SDS-PAGE可见诱导表达的样品在分子量大约59 ku处有明显条带,经Western blotting可与肺炎支原体免疫血清发生反应。ELISA实验检测51份临床标本,由P1重组蛋白抗原检测阳性31份,阳性率为60.78%。Mp检测阳性20份,阳性率为39.22%。实验精确度检测阳性混合血清的变异系数(CV值)为5.40%,阴性混合血清变异系数为1.10%。用Mp P1重组蛋白抗原建立的ELISA检测方法,其敏感性高于全肺炎支原体抗原,可用于临床肺炎支原体感染的诊断。     

GFP质控芯片的初步研究

目的：建立一种质量控制芯片来监测样品标记、杂交和检测过程中的失误。方法：针对GFP基因设计的4条60mer寡核苷酸探针和1条阳性对照探针polv（U）与流感寡核苷酸探针一起打印在DAKO玻片上,并构建了GFP基因的克隆载体和体外表达载体,将从这两种重组载体上获得的绿色荧光蛋白（Green Fluorescent Protein,GFP）基因的ILNA、DNA片段和人的全血样品中的DNA用限制性显示技术（Restriction Display technology,RD）扩增标记,将标记的样品和荧光标记的通用引物U分别与芯片杂交、检测,并对扫描的结果进行统计分析。结果：GFP探针与相应的样品杂交时出现阳性信号,阳性对照探针在所有的杂交中均出现阳性信号,而空白对照则未检测荧光信号。结论：建立的质控芯片具有较好的敏感性和特异性,可以用于基因芯片中的质量监控。     

A comparison of variability in Papanicolaou and liquid-based cytology inadequacy rates using Shewhart control charts

OBJECTIVE: To use Shewhart control charts to compare variability in inadequacy rates from Papanicolaou (Pap) and liquid-based cytology (LBC). DESIGN: Retrospective analysis of quality assurance data. SETTING: Eleven Welsh cytology laboratories. METHODS: Shewhart 'p' charts were plotted for proportions of slides reported as inadequate. Charts were compared for statistical control. MAIN OUTCOME MEASURES: Evidence of statistical control in the processes. RESULTS: Control charts allowed easy interpretation of patterns in the data. Variability in inadequacy rates was much lower for LBC than for Pap cytology. CONCLUSION: Monitoring inadequate rates with Shewhart charts provides more information than tabular monitoring reports, assisting in quality improvement. With respect to inadequacy rates, LBC is less variable than Pap cytology.     

Technical considerations for the performance of Nucleic acid Amplification Technology (NAT). The NAT Task Force Group.

The complexity of Nucleic acid Amplification Technology (NAT(1)), comprising sample preparation, amplification and detection methods, requires specific design considerations for both the laboratory and the procedures utilized in such testing. The purpose of this paper is to establish technical considerations for the performance of NAT. These include the collection, handling and assay of specimens and the design of laboratories to routinely and reliably detect low levels of nucleic acid sequences. The sensitivity of NAT due to the exponential amplification of nucleic acids makes contamination a major concern from specimen collection to sample detection. Therefore, laboratories need to be designed to prevent and control contamination through adequate equipment and appropriate workflow. These technical considerations should provide a basis for establishing a robust and reproducible NAT system.     

Raman spectroscopy and chemometrics for on‐line control of glucose fermentation by Saccharomyces cerevisiae

This work presents the use of Raman spectroscopy and chemometrics for on‐line control of the fermentation process of glucose by Saccharomyces cerevisiae. In a first approach, an on‐line determination of glucose, ethanol, glycerol, and cells was accomplished using multivariate calibration based on partial least squares (PLS). The PLS models presented values of root mean square error of prediction (RMSEP) of 0.53, 0.25, and 0.02% for glucose, ethanol and glycerol, respectively, and RMSEP of 1.02 g L^?1 for cells. In a second approach, multivariate control charts based on multiway principal component analysis (MPCA) were developed for detection of fermentation fault‐batch. Two multivariate control charts were developed, based on the squared prediction error (Q) and Hotelling's T². The use of the Q control chart in on‐line monitoring was efficient for detection of the faults caused by temperature, type of substrate and contamination, but the T² control chart was not able to monitor these faults. On‐line monitoring by Raman spectroscopy in conjunction with chemometric procedures allows control of the fermentative process with advantages in relation to reference methods, which require pretreatment, manipulation of samples and are time consuming. Also, the use of multivariate control charts made possible the detection of faults in a simple way, based only on the spectra of the system. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012     

Limnological research can improve and reduce the cost of monitoring and control of water quality

An evaluation of the programmes for control and monitoring of water quality in Sweden has demonstrated many short-comings. This paper discusses how improvements can be achieved by using new limnological knowledge.High-frequency sampling and analysis of mixed samples gives reliable average values with reduced costs. Strong correlations between, for instance, summer average values and summer maximum values, can be used for predicting the worst possible situation, which would be difficult to analyse by low-frequency sampling. Phosphorus load and lake response relationships are valuable tools for lake management and for establishing water quality criteria in physical planning. Future control may be further improved if limnological research gives better information on relationships between structure and function of aquatic ecosystems in relation to the form and size of the water body, water flushing rate, inputs from watershed and air space, etc.     

Optimal Designs of the Median Run Length Based Double Sampling X? Chart for Minimizing the Average Sample Size

Designs of the double sampling (DS) chart are traditionally based on the average run length (ARL) criterion. However, the shape of the run length distribution changes with the process mean shifts, ranging from highly skewed when the process is in-control to almost symmetric when the mean shift is large. Therefore, we show that the ARL is a complicated performance measure and that the median run length (MRL) is a more meaningful measure to depend on. This is because the MRL provides an intuitive and a fair representation of the central tendency, especially for the rightly skewed run length distribution. Since the DS chart can effectively reduce the sample size without reducing the statistical efficiency, this paper proposes two optimal designs of the MRL-based DS chart, for minimizing (i) the in-control average sample size (ASS) and (ii) both the in-control and out-of-control ASSs. Comparisons with the optimal MRL-based EWMA and Shewhart charts demonstrate the superiority of the proposed optimal MRL-based DS chart, as the latter requires a smaller sample size on the average while maintaining the same detection speed as the two former charts. An example involving the added potassium sorbate in a yoghurt manufacturing process is used to illustrate the effectiveness of the proposed MRL-based DS chart in reducing the sample size needed.