Permissible limits for uncertainty of measurement in laboratory medicine

AbstractThe international standard ISO 15189 requires that medical laboratories estimate the uncertainty of their quantitative test results obtained from patients’ specimens. The standard does not provide details how and within which limits the measurement uncertainty should be determined. The most common concept for establishing permissible uncertainty limits is to relate them on biological variation defining the rate of false positive results or to base the limits on the state-of-the-art. The state-of-the-art is usually derived from data provided by a group of selected medical laboratories. The approach on biological variation should be preferred because of its transparency and scientific base. Hitherto, all recommendations were based on a linear relationship between biological and analytical variation leading to limits which are sometimes too stringent or too permissive for routine testing in laboratory medicine. In contrast, the present proposal is based on a non-linear relationship between biological and analytical variation leading to more realistic limits. The proposed algorithms can be applied to all measurands and consider any quantity to be assured. The suggested approach tries to provide the above mentioned details and is a compromise between the biological variation concept, the GUM uncertainty model and the technical state-of-the-art.

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Optimizing the use of the “state-of-the-art” performance criteria

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2014-1201 ◽

2015 ◽

Vol 53 (6) ◽

Cited By ~ 3

Author(s):

Rainer Haeckel ◽

Werner Wosniok ◽

Thomas Streichert

Keyword(s):

State Of The Art ◽

Clinical Chemistry ◽

Reference Interval ◽

German Society ◽

Laboratory Medicine ◽

Biological Variation ◽

The State ◽

Analytical Performance ◽

Performance Criteria ◽

Performance Goals

AbstractThe organizers of the first EFLM Strategic Conference “Defining analytical performance goals” identified three models for defining analytical performance goals in laboratory medicine. Whereas the highest level of model 1 (outcome studies) is difficult to implement, the other levels are more or less based on subjective opinions of experts, with models 2 (based on biological variation) and 3 (defined by the state-of-the-art) being more objective. A working group of the German Society of Clinical Chemistry and Laboratory Medicine (DGKL) proposes a combination of models 2 and 3 to overcome some disadvantages inherent to both models. In the new model, the permissible imprecision is not defined as a constant proportion of biological variation but by a non-linear relationship between permissible analytical and biological variation. Furthermore, the permissible imprecision is referred to the target quantity value. The biological variation is derived from the reference interval, if appropriate, after logarithmic transformation of the reference limits.

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Transition to ISO 15189 : 2012 for Cytopathology Laboratories Part 1

International Journal of Reliable and Quality E-Healthcare ◽

10.4018/ijrqeh.2016070101 ◽

2016 ◽

Vol 5 (3) ◽

pp. 1-21 ◽

Cited By ~ 1

Author(s):

Eleftherios Vavoulidis ◽

Stavros Archondakis ◽

Maria Nasioutziki ◽

Ourania Oustambasidou ◽

Angelos Daniilidis ◽

...

Keyword(s):

Quality Management System ◽

State Of The Art ◽

Laboratory Medicine ◽

Quality Level ◽

Highly Qualified ◽

High Quality ◽

Iso 15189 ◽

Medical Laboratories ◽

Qualified Personnel ◽

Analytical Equipment

Nowadays, due to the latest advances in Laboratory Medicine, diagnostic medical laboratories with their highly qualified personnel and state-of-the-art analytical equipment, have completely changed the way modern healthcare is offered. In order to maintain or even increase the already high quality level of the provided testing services, diagnostic laboratories including the cytopathology ones, need to design and apply a Quality Management System (QMS) in agreement with the requirements of the ISO 15189 International Standard. The authors present their experience on the implementation of such a QMS in cytopathology laboratories and highlight the most important general and management parameters that should be taken into consideration when moving from ISO 15189:2007 to the latest ISO 15189:2012. In addition, useful recommendations and suggestions that could make the transition to the latest Standard easier are included. Finally, possible issues and potential adverse events associated with the laboratory's implementation of the ISO 15189:2012 are also described.

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Flexible scope for ISO 15189 accreditation: a guidance prepared by the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Working Group Accreditation and ISO/CEN standards (WG-A/ISO)

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2015-0257 ◽

2015 ◽

Vol 53 (8) ◽

Cited By ~ 8

Author(s):

Marc H.M. Thelen ◽

Florent J.L.A. Vanstapel ◽

Christos Kroupis ◽

Ines Vukasovic ◽

Guilaime Boursier ◽

...

Keyword(s):

Working Group ◽

Clinical Chemistry ◽

Laboratory Medicine ◽

Position Paper ◽

European Federation ◽

Medical Field ◽

Iso 15189 ◽

Medical Laboratories ◽

Flexible Scope ◽

Scientific Disciplines

AbstractThe recent revision of ISO15189 has further strengthened its position as the standard for accreditation for medical laboratories. Both for laboratories and their customers it is important that the scope of such accreditation is clear. Therefore the European co-operation for accreditation (EA) demands that the national bodies responsible for accreditation describe the scope of every laboratory accreditation in a way that leaves no room for doubt about the range of competence of the particular laboratories. According to EA recommendations scopes may be fixed, mentioning every single test that is part of the accreditation, or flexible, mentioning all combinations of medical field, examination type and materials for which the laboratory is competent. Up to now national accreditation bodies perpetuate use of fixed scopes, partly by inertia, partly out of fear that a too flexible scope may lead to over-valuation of the competence of laboratories, most countries only use fixed scopes. The EA however promotes use of flexible scopes, since this allows for more readily innovation, which contributes to quality in laboratory medicine. In this position paper, the Working Group Accreditation and ISO/CEN Standards belonging to the Quality and Regulation Committee of the EFLM recommends using an approach that has led to successful introduction of the flexible scope for ISO15189 accreditation as intended in EA-4/17 in The Netherlands. The approach is risk-based, discipline and competence-based, and focuses on defining a uniform terminology transferable across the borders of scientific disciplines, laboratories and countries.

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Neue Anforderungen aus der Normung und Akkreditierung nach ISO/DIS 15189:2011 – Der State of the Art-Ansatz für Qualität und Kompetenz in medizinischen Laboratorien/New requirements from standardization and accreditation – the state of the art concept for quality and competence in medical laboratories

LaboratoriumsMedizin ◽

10.1515/labmed-2011-0035 ◽

2012 ◽

Vol 36 (6) ◽

Author(s):

Folker Spitzenberger ◽

Gerhard Weidemann

Keyword(s):

State Of The Art ◽

The State ◽

Medical Laboratories

ZusammenfassungDer neue ISO-Normentwurf ISO/DIS 15189:2011 „Medizinische Laboratorien – Besondere Anforderungen an die Qualität und Kompetenz“ stellt deutlich erweiterte Anforderungen an das Qualitätsmanagementsystem in medizinischen Laboratorien. Die Änderungen lassen sich dabei in drei Kategorien differenzieren: redaktionelle, strukturelle und inhaltliche Änderungen. Die wesentlichen Aspekte der auch im Rahmen der Akkreditierung anzuwendenden Norm betreffen inhaltlich sowohl novellierte Anforderungen an das Management als auch technische Anforderungen. Im Mittelpunkt der Dokumentation des Qualitätsmanagementsystems stehen neben dem QM-Handbuch zukünftig mehr als 20 „dokumentierte Verfahren“, die obligatorisch zu erstellen sind. Hinsichtlich der Beauftragung von Fremdlaboratorien als Unterauftragnehmer fordert der Normentwurf durch eindeutige Kennzeichnungspflichten eine deutlich erhöhte Transparenz für Patienten und Einsender. Konzepte wie Risikomanagement und erweiterte Reviewaktivitäten werden neu eingeführt. Im Rahmen der technischen Anforderungen liegt der Schwerpunkt auf einer Konkretisierung der Kriterien bezüglich der Verifizierung/Validierung von Untersuchungsverfahren und der Sicherstellung der Qualität der Untersuchungsergebnisse. Die zukünftige Norm fordert – entsprechend dem definitionsgemäß reflektierten Stand von Wissenschaft und Technik – die Einhaltung von definierten Qualitätskriterien bei der Befundvalidation und im Rahmen des Informationsmanagements eines Laboratoriums. Im regulatorischen Kontext ist der neue Normentwurf in die anstehende Revision des europäischen Medizinprodukterechts eingebunden, die auch In-vitro-Diagnostika einschließt und national im Medizinproduktegesetz umgesetzt wird.

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Performance criteria and quality indicators for the post-analytical phase

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2015-0897 ◽

2016 ◽

Vol 54 (7) ◽

Cited By ~ 20

Author(s):

Laura Sciacovelli ◽

Ada Aita ◽

Andrea Padoan ◽

Michela Pelloso ◽

Giorgia Antonelli ◽

...

Keyword(s):

Quality Indicators ◽

State Of The Art ◽

Clinical Chemistry ◽

Laboratory Medicine ◽

The State ◽

Performance Criteria ◽

Quality Improvement Strategy ◽

Laboratory Errors ◽

Analytical Phase ◽

Over Time

AbstractQuality indicators (QIs) used as performance measurements are an effective tool in accurately estimating quality, identifying problems that may need to be addressed, and monitoring the processes over time. In Laboratory Medicine, QIs should cover all steps of the testing process, as error studies have confirmed that most errors occur in the pre- and post-analytical phase of testing. Aim of the present study is to provide preliminary results on QIs and related performance criteria in the post-analytical phase.This work was conducted according to a previously described study design based on the voluntary participation of clinical laboratories in the project on QIs of the Working Group “Laboratory Errors and Patient Safety” (WG-LEPS) of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC).Overall, data collected highlighted an improvement or stability in performances over time for all reported indicators thus demonstrating that the use of QIs is effective in the quality improvement strategy. Moreover, QIs data are an important source for defining the state-of-the-art concerning the error rate in the total testing process. The definition of performance specifications based on the state-of-the-art, as suggested by consensus documents, is a valuable benchmark point in evaluating the performance of each laboratory.Laboratory tests play a relevant role in the monitoring and evaluation of the efficacy of patient outcome thus assisting clinicians in decision-making. Laboratory performance evaluation is therefore crucial to providing patients with safe, effective and efficient care.

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A pragmatic proposal for permissible limits in external quality assessment schemes with a compromise between biological variation and the state of the art

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2011-0862 ◽

2012 ◽

Vol 50 (5) ◽

Cited By ~ 2

Author(s):

Rainer Haeckel ◽

Werner Wosniok ◽

Josef Kratochvila ◽

Anna Carobene

Keyword(s):

Quality Assessment ◽

External Quality Assessment ◽

State Of The Art ◽

Simple Algorithm ◽

Biological Variation ◽

The State ◽

National Guidelines ◽

External Quality ◽

Technical Feasibility ◽

Permissible Limits

AbstractPermissible limits for internal and external quality assurance are either based on biological variation or on the state of the art (technical feasibility). The former approach has a scientific basis, but, in some cases, leads to limits which are either not achievable under the present technology, or which are not stringent enough. If proficiency testing is mandatory, stringent limits which cannot be fulfilled by the majority of laboratories could lead to juristic consequences. Therefore, most national guidelines were based on the state of the art, however, without providing the underlying reasoning. A simple algorithm for permissible limits in external quality assessment schemes (EQAS) is proposed based on biological variation, technical feasibility and correlated to the rate of false positive results. The proposed limits are compared with some limits from several EQAS (RiliBÄK, SEKK, RCPA, CLIA, PROLARIT). The suggested limits are slightly more stringent than the German RiliBÄK, less stringent than the Australasian guidelines and agreed best with the Czech SEKK and the Italian PROLARIT scheme. The graphical presentation of permissible limits strictly derived of biological variation with the proposed limits led to straight lines with different slopes and a cross-over at the limits for quantities with a medium biological variation (e.g., trijodthyronine). The greatest discordance between the various recommendations was observed for calcium, chloride, hemoglobin A

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ISO 15189 Accreditation: Navigation Between Quality Management and Patient Safety

Journal of Medical Biochemistry ◽

10.1515/jomb-2017-0038 ◽

2017 ◽

Vol 36 (3) ◽

pp. 225-230 ◽

Cited By ~ 2

Author(s):

Mario Plebani ◽

Laura Sciacovelli

Keyword(s):

Clinical Laboratory ◽

Laboratory Medicine ◽

European Federation ◽

Quality Systems ◽

Iso 17025 ◽

Iso 15189 ◽

International Standard ◽

Medical Laboratories ◽

Laboratory Services ◽

Total Testing Process

SummaryAccreditation is a valuable resource for clinical laboratories and the development of an International Standard for their accreditation represented a milestone on the path towards improved quality and safety in laboratory medicine. The recent revision of the International Standard, ISO 15189, has further strengthened its value not only for improving the quality system of a clinical laboratory but also for better answering the request for competence, focus on customers’ needs and ultimate value of laboratory services. Although in some countries more general standards such as ISO 9001 for quality systems or ISO 17025 for testing laboratories are still used, there is increasing recognition of the value of ISO 15189 as the most appropriate and useful standard for the accreditation of medical laboratories. In fact, only this International Standard recognizes the importance of all steps of the total testing process, namely extra-analytical phases, the need to focus on technical competence in addition to quality systems, and the focus on customers’ needs. However, the number of accredited laboratories largely varies between European countries and also major differences affect the approaches to accreditation promoted by the national bodies. In particular, some national accreditation bodies perpetuate the use of fixed scopes, while the European co-operation for accreditation (EA) and the European Federation of Laboratory Medicine (EFLM) Working Group promote the use of flexible scopes. Major issues in clinical laboratory accreditation are the verification of examination procedures for imprecision, trueness and diagnostic accuracy and for estimating measurement uncertainty. In addition, quality indicators (QIs) are a fundamental requirement of the ISO 15189 International Standard.

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Practical Picture Processing

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051700 ◽

1974 ◽

Vol 32 ◽

pp. 338-339

Author(s):

T. A. Welton

Keyword(s):

Radiation Damage ◽

Coherence Length ◽

Spatial Information ◽

State Of The Art ◽

Coherent Radiation ◽

The State ◽

Energy Spread ◽

Electron Micrograph ◽

Picture Processing ◽

Molecular Skeleton

Various authors have emphasized the spatial information resident in an electron micrograph taken with adequately coherent radiation. In view of the completion of at least one such instrument, this opportunity is taken to summarize the state of the art of processing such micrographs. We use the usual symbols for the aberration coefficients, and supplement these with £ and 6 for the transverse coherence length and the fractional energy spread respectively. He also assume a weak, biologically interesting sample, with principal interest lying in the molecular skeleton remaining after obvious hydrogen loss and other radiation damage has occurred.

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