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Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement (v.9, #1-2)
Comparative study of the presentations at the CCQM workshop on traceability
by Wolfgang Richter (pp. 2-4).
Establishing measurement traceability in clinical chemistry by L. Siekmann (pp. 5-17).
Measurement traceability is probably the most important tool for achievement of comparability in clinical chemistry. As stipulated by the In Vitro Diagnostica Directive of the European Union and several ISO standards, values assigned to calibrators and control materials must be traceable to reference materials and/or reference procedures of higher order. In the German proficiency testing system, statutory use of reference measurement procedures for several measurands has been in force since 1988. As a result, reference procedures are now regularly applied for the setting up of target values in the control samples of internal and external quality assessment and for assigning values to the manufacturer’s calibrator and control materials. Noticeably, the comparability of results obtained by different diagnostic tests has greatly improved for the measurement of many metabolites and substrates, e.g. creatinine, cholesterol, uric acid, total glycerol and urea. For many measurands in laboratory medicine the implementation of the concept of traceability proves to be much more difficult; this mainly concerns the measurement of proteins, in particular enzymes, proteo-hormones, tumour markers and cardiac markers. For such measurands the analyte must first of all be distinctively defined before a reference system can be established which comprises reference procedures, reference materials and networks of reference laboratories.
Keywords: Traceability; Clinical chemistry; Reference measurement procedure; Isotope dilution mass spectrometry (IDMS); External quality assessment
Clinical Laboratory Reference Networks by Mary M. Kimberly; Gary L. Myers; Randie R. Little (pp. 18-23).
The Centers for Disease Control and Prevention, or CDC, has a long history of providing traceability in clinical laboratory medicine. Early work was to develop reference methods for important clinical analytes. When the National Cholesterol Education Program issued recommendations for physicians and clinical laboratories for measurement of lipids and lipoproteins, CDC formed the Cholesterol Reference Method Laboratory Network (CRMLN) to provide manufacturers with access to the accuracy bases. The CRMLN assists manufacturers with calibration of diagnostic products to ensure traceability to higher-order technology. A certification program for manufacturers assures the clinical laboratory community that these products are accurate and precise. The CRMLN model for traceability has been applied to other networks, notably the National Glycohemoglobin Standardization Program.
Keywords: Reference networks; Standardization; Lipids; Lipoproteins; Glycated hemoglobin
One way of disseminating reference values with demonstrated traceability and demonstrated uncertainty to field laboratories: IMEP by Philip Taylor (pp. 24-32).
An operational interlaboratory comparison programme is described which disseminates SI-traceable reference values to laboratories worldwide. These reference values have an uncertainty and traceability that is demonstrated at the highest metrological level. Participating laboratories can use these values to establish the degree of equivalence of their measurement results and can use this to support their measurement capability claims, e.g. towards third parties. The programme has been run by the Institute for Reference Materials and Measurements (IRMM) since 1988, in the first phase as an awareness programme. Currently, IRMM is focusing its efforts on educational aspects of metrology via a collaboration with the European Co-operation for Accreditation, national metrological institutes (NMIs) and interested academic networks. The viewgraphs used are presented in the “Electronic Supplementary Material” of this ACQUAL issue.
Achieving traceable chemical measurements: inter-laboratory evaluation of a simplified technique for isotope dilution mass spectrometry (IDMS). Part 1: Methodology for high accuracy analysis of trace metals by Rita Harte; Gerry Newman; Mike Sargent (pp. 33-38).
A high accuracy measurement procedure developed and validated at the Laboratory of the Government Chemist (LGC) has been transferred to a number of expert United Kingdom laboratories and their experience in applying the technique has been evaluated by inter-laboratory comparisons. It is an “approximate matching” calibration procedure for analysis of trace metals using isotope dilution mass spectrometry (IDMS). Use of a calibration blend and a sample blend having closely matched isotope amount ratios reduces systematic errors. Four comparisons were carried out, each evaluating an increasingly difficult aspect of the methodology. The final study required determination of trace levels of cadmium in an artificial food matrix acid digest containing tin, using both external calibration and approximate matching IDMS. The results of the trials clearly showed the superior accuracy of the IDMS approximate matching procedure; a result within 1% of the target reference value could be achieved. These trials and a training workshop enabled LGC to transfer its methodology to other expert laboratories, helping to improve the United Kingdom delivery of traceable reference measurements.
Keywords: Isotope dilution; IDMS; Approximate matching; Traceability
ISO 9001 has had no effect on quality in the in vitro medical diagnostics industry by Jan S. Krouwer (pp. 39-43).
ISO 9001 certification (currently ISO 9000:2000) implies that an organization is managed in a quality manner. ISO certification is primarily achieved by audits that show that a company follows its own procedures. These procedures are prepared by the company with few ISO requirements. ISO procedures are flawed in two ways: they can represent only part of what an organization does within a process, and they often lack sufficient detail. The latter limitation allows both adequate and inadequate tasks. Often, people pay attention to ISO only when audits are imminent, which contrasts with other quality initiatives that have goals directly related to quality with frequent measurements and continual involvement by staff. There does not appear to be any connection between company successes or failures and ISO certification, and failing an ISO audit is a rare event. All of this leads one to conclude that ISO 9001 has had no effect on quality. In addition, there is a danger that “flexible” or so-called horizontal ISO standards that lack detail will supplant more traditional standards, which prescribe a procedure that has been agreed to by a consensus of experts. Improving ISO 9001 starts with recognizing its limitations. Recommendations regarding ISO certification include: dropping it, minimizing resource allocation to it, and trying to change it.
Keywords: ISO 9000; Quality; Certification; ISO 9001; In vitro medical diagnostics
Measurement uncertainty—policy and guidance documents issued by accreditation bodies by Ulf Örnemark (pp. 44-46).
ISO/IEC 17025 contains general requirements for the competence of calibration and testing laboratories, including those for the evaluation and reporting of measurement uncertainty. Some accreditation bodies have issued additional guidance documents and regulations related to uncertainty, five of which are briefly commented on here.
Keywords: Measurement uncertainty; Testing; Chemical analysis; Accreditation; Policies
Implementation of traceability and uncertainty in in-vitro diagnostic products—Results of the Roche workshop “In Vitro Diagnostics Directive”: Practical applications of uncertainty calculations by Johanna Andersson; Yvonne Couchér; Hans Kjer; Solveig Linko; Britt-Marie Ödlund; Emil Völkert (pp. 47-51).
The European Commission (EC) Directive on in vitro diagnostic medical devices requires—amongst other obligations—manufacturers to establish metrological traceability of values assigned to calibrators to available measurement procedures and/or available reference materials of a higher order. Manufacturers use different procedures to accomplish this task and to indicate uncertainties of assigned values. Medical laboratories may want to calculate the uncertainties of their results or accreditation bodies may require them to do so. For this purpose some practical approaches are presented and some examples discussed.
Keywords: In vitro diagnostics directive; IVD; Calibrator; Traceability; Uncertainty
Laboratory accreditation: Proof of performance for environmental laboratories—2001 study by Andrew Morris; Debbie Macey (pp. 52-54).
“Do accredited environmental laboratories actually perform better?” The Canadian Association for Environmental Analytical Laboratories (CAEAL) attempted to answer this question in a 1997 article entitled “Laboratory Accreditation: Proof of Performance for Environmental Labs” (Canadian Chemical News, September 1997). Since that time we have received numerous requests to repeat the performance comparison. Since we now have data from additional years of proficiency testing (PT) studies, we have repeated the original study. CAEAL is committed to working with the laboratory community and their clients to achieve and demonstrate the value of implementing the highest quality standards in Canadian environmental laboratories. To this end, CAEAL and the Standards Council of Canada (SCC) jointly deliver an accreditation program for environmental laboratories in Canada. The accreditation program is based on ISO/IEC 17025 “General Requirements for the Competence of Testing and Calibration Laboratories”. Laboratory performance for many accredited parameters is evaluated through interlaboratory PT, and laboratory capability is assessed every 2 years by a laboratory site assessment covering the lab’s quality system and its technical capabilities for the specific tests. By mid 2001, more than 120 environmental labs were participating in the joint SCC/CAEAL accreditation program, representing about 38% of all labs accredited by the SCC for all areas of testing. Another 160 to 170 labs are involved in only PT, making a total of 270 to 280 labs in CAEAL’s PT program.
Keywords: Laboratory accreditation; Proficiency testing; Biological oxygen demand; Total suspended solids; Fecal coliforms
An uncertainty budget for the determination of the purity of glyphosate by quantitative nuclear magnetic resonance (QNMR) spectroscopy by Tareq Saed Al-Deen; D. Brynn Hibbert; James M. Hook; Robert J. Wells (pp. 55-63).
An uncertainty budget is presented for the results of measurements of purity of the agrochemical glyphosate using 1H and 31P quantitative nuclear magnetic resonance (QNMR) spectroscopy. The budget combines intralaboratory precision from repeated independent measurements of a batch, and other Type A and Type B effects. Consideration of correlation of uncertainties in ratios of mass determinations has been included. Expanded uncertainties of the purity for single determinations of purity by 1H and 31P QNMR are 0.66% and 0.82% (95% confidence interval, k=2), respectively.
Keywords: Uncertainty budget; Measurement uncertainty; Method validation; Quantitative nuclear magnetic resonance (QNMR); Glyphosate; Agrochemicals
Estimation of measurement uncertainty by the budget approach for heavy metal content in soils under different land use by Ulrich Kurfürst; André Desaules; Albert Rehnert; Herbert Muntau (pp. 64-75).
A reference database was used for the estimation of the standard uncertainties resulting from sampling, sample preparation, and analysis of soil samples from a target area in Switzerland. This evaluation was based on an extended reference sampling of the Comparative Evaluation of European Methods for Sampling and Sample Preparation of Soils Project. Samples were taken according to the national sampling protocols of 15 European countries and were analyzed for zinc, cadmium, copper, and lead. The combined uncertainty for all laboratories was estimated according to the ISO Guide to the Expression of Uncertainty in Measurement. It was found that the sampling uncertainty was not larger than the analytical uncertainty if more than ten sample increments were taken. The uncertainty due to variation in sampling depth and sample size reduction was only significant under unfavorable conditions. On the basis of an uncertainty budget the sampling protocols can be optimized and a ranking is possible, aimed at conditions that are fit for the specific purpose.
Keywords: Soil sampling; Sampling effects; Reference sampling; Measurement uncertainty; Trace elements
Validation of the RP–HPLC method for analysis of hydrochlorothiazide and captopril in tablets by D. Ivanovic; M. Medenica; A. Malenovic; B. Jancic (pp. 76-81).
A rapid and sensitive reverse-phase high performance liquid chromatography (RP–HPLC) method with ultra-violet (UV) detection for a routine control of hydrochlorothiazide and captopril in tablets was developed. The chromatographic system Hewlet Packard 1100 consisted of a HP 1100 pump, HP 1100 UV–VIS detector and HP ChemStation integrator. The samples were introduced through a Rheodyne injector valve with a 20-μL sample loop. The isocratic system consisted of a Beckman Ultrasphere ODS 4.6 mm x 15 cm, 5-μm-particle column and a mobile phase containing methanol/water (45:55 v/v). The pH of the mobile phase was adjusted to 3.8 with 85% ortophosphoric acid. Quantitation was accomplished using the internal standard method. At the selected conditions, the other excipients of the tablets did not interfere in the assay of active substances. The developed RP–HPLC method was validated, so linearity, precision, accuracy, robustness, limit of quantitation and limit of detection were investigated. For the robustness test, three factors were considered: the composition of the mobile phase , the pH of the mobile phase, and temperature. With the aid of response surface metodology (RSM), it was possible to precisely define the robustness of the method.
Keywords: Validation; RP-HPLC; Hydrochlorothiazide; Captopril; Tablets
Evaluation of the long-term performance of water-analyzing laboratories by Wolfgang Kandler; Rainer Schuhmacher; Susanne Roch; Patricia Schubert-Ullrich; Rudolf Krska (pp. 82-89).
After 7 years of successful operation, the database of the proficiency testing (PT) scheme for water analysis organized by the Institute for Agrobiotechnology (IFA), Tulln contains nearly 4,000 data sets from over 300 interlaboratory comparison samples. About 70 analytical parameters (major ions, metals, trace ions, herbicides, volatile halogenated hydrocarbons, organochlorine pesticides and polycyclic aromatic hydrocarbons) were covered by the PT scheme. The data were evaluated using robust statistics in order to determine a set of coefficients of variation (CV) for each analytical parameter. Concentration and time dependence of the CV were checked. The CV were combined to obtain standard deviations for proficiency assessment (Z-score criteria). Furthermore, a viewer program was designed to facilitate monitoring of the analytical performance of participating laboratories.
Keywords: Interlaboratory comparisons; Proficiency testing; PT scheme; Z-scores; Water analysis
The view of laboratories’ clients on the value of accreditation by Magnus Holmgren (pp. 90-91).
The Swedish National Testing and Research Institute (SP) asked its clients in its 2001–2002 customer satisfaction survey how they valued an accredited test result on a scale of 1-6. As many as 81% of the recipients answered that it was important (a score of 5 or 6 on the scale ) to have an accredited test result. 12% found the question irrelevant, which could be interpreted as that they used some of SP’s non-accredited services, or were just not interested in accredited test reports.
Keywords: Accreditation; Customer satisfaction survey
Understanding the quality concept in health care by P. P. M. Harteloh (pp. 92-95).
During the past three decades there has been an intense debate on the quality of health care. Errors in medicine, practice variations, competence of physicians, scarcity and lack of resources have all been reasons for discussing the quality of care. A clear definition of quality should explain the nature of the debate, improve uniformity of speech and facilitate meaningful actions such as quality assurance or quality improvement. However, in due course many different definitions have been proposed and principles of quality assurance in health care have been frequently questioned, because of their industrial nature. It raises questions on our understanding of quality in health care. In this paper, we (i) explore the nature of the quality concept, (ii) explain its meaning by Wittgenstein's theory on rule-following, and (iii) argue for understanding medical care as a reflexive practice, in order to integrate the meaning of quality in medical care.
Support of laboratory accreditation in Central and Eastern Europe by preliminary assessment by Mica Jovanovic (pp. 96-98).
The development of a competent and reliable network of accredited laboratories represents one, among other, important means of removal of technical barriers to trade. The achievement of the goal “tested once-accepted everywhere” should be supported by carefully planned actions. The paper presents a detailed description of a proposal to develop European Cooperation for Accreditation (EA) laboratory multilateral recognition agreements in Central and Eastern European (CEE) countries by preliminary laboratory accreditation assessment. The proposed concept could be a valid supporting approach to EA procedures, removing the main obstacles that may be present in the accreditation bodies of CEE countries, prior to entering the formal evaluation process. The proposed technique is rapid and of low cost, yet it should give a broad overview of the accreditation body’s level of development.
Keywords: Laboratory accreditation; Mutual recognition agreement; Accreditation assessment
Implementation of ISO/IEC 17025 Standard for the accreditation of analytical laboratories in Russia by I. V. Boldyrev; Yu. A. Karpov (pp. 99-105).
The history since 1992 and the current state of affairs of the Russian Accreditation system for analytical laboratories are described. Some national characteristics of the implementation of the ISO/IEC 17025 Standard in Russia are considered. The elucidation of some ISO/IEC 17025 Standard prepositions is presented to facilitate implementation of the Standard by accreditation bodies and analytical laboratories claiming accreditation.
Keywords: ISO/IEC 17025 Standard; Accreditation; Accreditation body; Analytical laboratory
Target measurement uncertainties for results of chemical measurements in Slovenia by Nineta Majcen; Ivan Skubic; Paul De Bièvre (pp. 106-111).
Target measurement uncertainties (TMUs), which should be achieved in chemical measurements, are proposed. Such TMUs are intended to set goals for measurement laboratories and could provide independent and objective criteria for laboratory assessors verifying the measurement capability of laboratories. A TMU is specified relative to a stated metrological reference for the measurand concerned. TMUs are common and objective, but are external criteria for both the measurement laboratories and their assessors. They are decided on the basis of the intended use of the measurement result, not evaluated as is the case for measurement uncertainty. The concept of TMU is illustrated by means of desirable applications in food measurements in Slovenia.
Keywords: Measurement uncertainty; Measurements in chemistry; Quality of food; Technical legislation
Physiological reference values: a shared business? Report of the second European symposium on clinical laboratory and in vitro diagnostics industry by Núria Monge-Azemar; Luz María Cruz-Carlos; Xavier Fuentes-Arderiu (pp. 112-114).
The Catalan Association of Clinical Laboratory Sciences, with the support of its corporative members, organized the second European symposium devoted to physiological reference values, in Barcelona. The objectives were: (i) to discuss ways to develop a common strategy among clinical laboratories and the in vitro diagnostic (IVD) industry for the generation of physiological reference values related to biological quantities of medical interest; and (ii) to establish consensus between both groups regarding the interpretation of the requirements related to physiological reference values contained in the European (EU) Directive 98/79-EC and in the EN-ISO 15189:2003 standard. The symposium was divided into four parts in which different aspects of the reference values were discussed: legal and normative aspects, alternatives to the production of own reference values, methodology, and diffusion and teaching. The main conclusions were the need to clarify the requirements described by the EU Directive 98/79-EC and EN-ISO 15189:2003 regarding reference values, and the need for cooperation between industry, clinical laboratories, and health authorities to achieve common reference intervals, including multicentric reference intervals.
Keywords: Reference values; IVD industry; EU Directive 98/79-EC; EN-ISO 15189:2003