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1.
The setting of analytical quality specifications in laboratory medicine has attracted attention for many years. Over time, many strategies were advocated and all had advantages and disadvantages. In the final decade of the last millennium, considerable confusion existed on how to define analytical quality specifications correctly and how to apply them in everyday practice. This led to wide professional interest. In 1999, a consensus conference sponsored by IUPAC, IFCC and WHO was held in Stockholm on “Strategies to Set Global Analytical Quality Specifications in Laboratory Medicine”. The consensus set useful and well-documented strategies for the setting of analytical quality specifications into a hierarchy with the best strategy at the highest level, namely, (1) Evaluation of the effect of analytical performance on clinical outcomes in specific clinical situations, (2) Evaluation of the effect of analytical performance on clinical decisions in general, (3) Published professional recommendations, (4) Performance goals set by regulatory bodies and EQAS organisers, and (5) Goals based on the current state of the art. Much success has been achieved since the promulgation of the statement with the approach being adopted by many in laboratory medicine for a very wide variety of purposes, particularly in quality management. However, there is a requirement for additional investigation of, inter alia, quality specifications for examinations done on measurements performed on ordinal and nominal scales, pre-analytical factors and matrix effects, examinations done as POCT, target values of control materials, and ways in which analytical quality specifications can be used both to set what is the optimum performance and as a tool for assessment of everyday practice.  相似文献   

2.
Every analytical method used in laboratory medicine can be fully described in terms of its performance characteristics. Ideally, quality specifications should be available for all of these, particularly precision and bias. Specifications for these can be set using a variety of strategies. Consideration of the clinical settings of monitoring individual patients and diagnosis using reference intervals shows that generally applicable quality specifications can be based on the components of biological variation, namely, within-subject [CVI] and between-subject [CVG] variation. Current consensus is that precision should be <1/2CVI and bias should be <1/4[CVI 2+CVG 2]1/2. This strategy has advantages in that data on components of biological variation are easily available on more than 180 quantities. Dissemination of information on application of objective quality specifications needs attention from those involved in publication, manufacturers and organisers of external quality assessment schemes.  相似文献   

3.
Reporting reliable analytical data is the backbone of forensic and clinical bioanalytical research and applications. Therefore, international agreement concerning validation and quality control requirements is needed. Several international guidelines provide a standard for fundamental validation parameters such as selectivity, matrix effects, method limits, calibration, accuracy, precision and stability. However, it is not always easy for the analyst to ‘translate’ these guidelines into practice. International guidelines remain nonbinding protocols that need to be updated according to the type of application and the analyst’s method requirements and depends on the evolution of analytical techniques. In this publication, suggestions for experimental set-up, statistical approaches and straightforward acceptance criteria for validation of forensic bioanalytical applications are suggested. Furthermore, permanent quality control, to ensure state-of-the-art quantitative analytical performances, as well as measurement uncertainty influencing interpretation is discussed.  相似文献   

4.
 The fact that various definitions and terminology applied to measurements in analytical chemistry are not always consistent and straightforward, by not only answering the question ”what”, but also ”how”, leads to their various interpretations. This results in non-uniform implementation of very basic and essential metrological principles in chemistry. Such a diverse situation is not conducive to the endorsement of harmonised measurements all across the world, to serve as a tool for improving the quality of life in its broadest sense for all its citizens. The discussion in this paper is focused on problems associated with terminology and definitions of ’reference material’ and ’validation’. The role of reference materials in measurement processes for purposes other than calibration and validation principles in analytical chemistry are also discussed in this paper. Where possible, potential solutions are proposed, but more often, questions of essential importance are raised in order to initiate international discussion which will hopefully lead to equally understandable answers. Received: 2 November 2002 Accepted: 3 February 2003 Acknowledgements   The author is grateful to Aleš Fajgelj for his comprehensive comments on the topic described in this paper. Sincere thanks also to Philip Taylor, Ewa Bulska, Emilia Vassileva, Miloslav Suchanek and Margreet Lauwaars for their contribution during fruitful discussions on validation. Presented at the CERMM-3, Central European Reference Materials and Measurements Conference: The function of reference materials in the measurement process, May 30–June 1, 2002, Rogaška Slatina, Slovenia Correspondence to N. Majcen  相似文献   

5.
The ‘characteristic function’ is a two-parameter function relating precision or uncertainty in analytical results to the concentration of the analyte. In previous papers, in this series, it has been shown to provide a good model of precision measured: (a) under reproducibility conditions and (b) under ‘instrumental’ conditions. The present study shows that it is also a valuable model for precision estimated under repeatability conditions. The study data were large sets of duplicated results obtained for the purposes of quality control on typical test materials in routine analysis. As the analytes exhibited concentration ranges encompassing between one and three orders of magnitude, there was ample scope to demonstrate goodness of fit to the function under different circumstances.  相似文献   

6.
The reliability of analytical data is very important to forensic and clinical toxicologists for the correct interpretation of toxicological findings. This makes (bio)analytical method validation an integral part of quality management and accreditation in analytical toxicology. Therefore, consensus should be reached in this field on the kind and extent of validation experiments as well as on acceptance criteria for validation parameters. In this review, the most important papers published on this topic since 1991 have been reviewed. Terminology, theoretical and practical aspects as well as implications for forensic and clinical toxicology of the following validation parameters are discussed: selectivity (specificity), calibration model (linearity), accuracy, precision, limits, stability, recovery and ruggedness (robustness). Received: 16 June 2002 Accepted: 12 July 2002 Part of this review was published in the communications of the International Association of Forensic Toxicologists (TIAFT; TIAFT Bulletin 32 (2002): 16–23) and of the Society for Forensic and Toxicologic Chemistry (GTFCH; Toxichem and Krimitech 68 (2001): 116-126). Correspondence to F. T. Peters  相似文献   

7.
This topic is being presented from two perspectives, namely the views of an accreditation body and those of an accredited provider of external quality assessment schemes. The first perspective, from an accreditation body, is based on the experience of Australia's national laboratory accreditation body (NATA), which has accredited fourteen proficiency testing (PT) providers and is currently processing an application from another. The second perspective is based on the experience of EQUALIS, the national quality assurance organisation for laboratory medicine in Sweden, which was granted accreditation in 2002.Presented at 5th Eurachem Workshop on Proficiency testing in analytical chemistry, microbiology and laboratory medicine, Portorož (Slovenia) 25–27 Sept 2005  相似文献   

8.
 The role of matrix reference materials in the process of demonstrating the degree of equivalence of measurement results obtained from intercomparisons is outlined, reviewing exemplary selected experience gained at BAM regarding the determination of organic contaminants in environmental matrices. The specific characteristics of reference materials employed in the process of demonstrating equivalence between laboratories in the course of proficiency testing as well as the development, comparison and validation of methods are elaborated. The demand is for series of appropriately characterised samples which are fit for the purpose and it is seen from representative examples that the utilisation of such tailor-made RM designed to tackle the specific need of an analytical problem dominates over certified matrix reference materials in this context. Concluding, the role of certified matrix reference materials in quality assurance is briefly looked at both from the user’s and providers’ points of view. Received: 9 September 2002 Accepted: 16 December 2002 Presented at CERMM-3, Central European Reference Materials and Measurements Conference: The function of reference materials in the measurement process, May 30–June 1, 2002, Rogaška Slatina, Slovenia Correspondence to R. Becker  相似文献   

9.
Historically, due to the size and nature of the instrumentation, highly skilled laboratory professionals performed clinical testing in centralized laboratories. Today’s clinicians demand realtime test data at the point of care. This has led to a new generation of compact, portable instruments permitting ”laboratory” testing to be performed at or near the patient’s bedside by nonlaboratory workers who are unfamiliar with testing practices. Poorly controlled testing processes leading to poor quality test results are an insidious problem facing point of care testing today. Manufacturers are addressing this issue through instrument design. Providers of clinical test results, regardless of location, working with manufacturers and regulators must create and manage complete test systems that eliminate or minimize sources of error. The National Committee for Clinical Laboratory Standards (NCCLS) in its EP18 guideline, ”Quality management for unit-use testing,” has developed a quality management system approach specifically for test devices used for point of care testing (POCT). Simply stated, EP18 utilizes a ”sources of error” matrix to identify and address potential errors that can impact the test result. The key is the quality systems approach where all stakeholders – professionals, manufacturers and regulators – collaboratively seek ways to manage errors and ensure quality. We illustrate the use of one quality systems approach, EP18, as a means to advance the quality of test results at point of care. Received: 26 June, 2002 Accepted: 17 July 2002 Presented at the European Conference on Quality in the Spotlight in Medical Laboratories, 7–9 October 2001, Antwerp, Belgium Abbreviations NCCLS National Committee for Clinical Laboratory Standards (formerly) · POCT point of care testing · QC quality control · HACCP hazard analysis critical control points · CLIA clinical laboratory improvement amendments (of 1988) Correspondence to S. S. Ehrmeyer  相似文献   

10.
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