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Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement (v.13, #9)


Comparison of different statistical methods for evaluation of proficiency test data by Pedro Rosario; José Luis Martínez; José Miguel Silván (pp. 493-499).
In analytical chemistry, proficiency testing usually consists in tests that laboratories conduct under routine conditions and report the result to the PT provider who then converts the result to a score which helps the participant to assess the accuracy of the result. The aim of this work is to show PT providers, accreditations bodies, and participating laboratories that different scoring results can be achieved depending on the evaluation system selected. The influence of different evaluation techniques on the results of an interlaboratory comparison for determination of gold in precious metals alloys was investigated. Results from 19 participating laboratories were evaluated by means of the three procedures: (1) classical statistical approach—outliers detection; (2) robust methods—(2A) robust procedure and (2B) ISO 13528; and (3) fitness for purpose. Evaluation of the same PT data revealed very interesting issues depending on the different scoring systems that were used and the robustness of the statistical methods used for detecting outliers. As a general rule, laboratories with scoring Z > 2 offered clearly poorer performance in robust approaches than classical ones. In order to support this first evidence, we evaluated a second data set with results from 24 laboratories (mercury from soil samples) by means of the four mentioned approaches. Selection and comparison of different scoring systems must be done very carefully, because sometimes they are not the best approach for studying the data population or the more appropriate one for evaluating the distribution of the data. Finally it should be taken into account that sometimes the robust scoring systems are not always suitable for evaluating the results of some PT schemes.

Keywords: Proficiency test data; Statistical methods; Evaluation; ISO 5725; Harmonized protocol; ISO 13528; Robust statistics; Fitness for purpose


External quality assessment in microbiology: comparison of results from Belgian and Canadian laboratories with regard to their ability to identify Streptococcus pyogenes by Kris Vernelen; Michael A. Noble; Jean-Claude Libeer (pp. 501-504).
Clinical Microbiology Proficiency Testing (CMPT; Canada) and the Institute of Public Health (IPH; Belgium) set up a joint external quality assessment (EQA) project in which they sent identical simulated clinical samples to their respective participants. Samples were sent out as throat swabs containing Streptococcus pyogenes (as pathogen) and viridans streptococci (as commensal). Results from identification by the Belgian laboratories were excellent: 99.5% detected the group A streptococci. About 10% of the Canadian laboratories reported the absence of reportable β-haemolytic streptococci, although for most of them the issue was one of non-examination of small or pin-point streptococci. Overall, Canadian and Belgian laboratories performed well in this EQA; the joint project clearly showed that although many similarities exist, there are differences between laboratories in treating EQA samples and reporting results.

Keywords: External quality assessment; Clinical samples; Microbiology; Streptococcus pyogenes


Aspects of auditing in clinical laboratories by Gurdeep Singh Dhatt; Sumedha Sahni; Hassan Abu Damir (pp. 505-509).
Quality and patient safety are terms that both providers and recipients of healthcare are very familiar with. Accreditation is another term that is closely linked to quality and patient safety. Audit is a systematic, independent, and documented process for obtaining evidence and evaluating it objectively to determine the extent to which audit criteria are fulfilled. Accreditation and audit are integral components of the same process. Three different types of audit are well recognized—internal, external, and co-operative. Reading of relevant documents, observation of laboratory practices, and asking open-ended probing questions are important auditing techniques. For auditing to be successful, experienced, qualified, and well trained auditors are essential. Furthermore, the auditor should be open-minded, not prejudiced, a team player and effective communicator, both in writing and verbally. In many instances, the emphasis for seeking laboratory accreditation has shifted from building quality systems—to produce reliable results and ensure patient safety—to just passing the inspection. Recently, the emphasis for laboratory quality improvement has been placed on pre and post-analytical processes in preference to analytical quality. The analytical quality of laboratory results is still far from ideal and it may be detrimental if less emphasis is placed on this aspect of laboratory medicine. Auditing or on-site inspection as a regulatory tool does not work or present a realistic picture of laboratory quality. A continuous quality improvement approach will help laboratories to build quality into their systems.

Keywords: Accreditation; Auditing; Continuous quality improvement; Inspectors


Current experiences with a quality management system for non-clinical research and development in pharmaceutical industry by Barbara Pohl; Stephanie Simon; Peter-Jürgen Kramer (pp. 511-521).
Quality management is one of the most important issues in pharmaceutical research as it determines the validity and reliability of data, data and data evaluation being the central products of all research activities. In this business it is of outstanding importance to generate valid data for the assessment of drug development candidates to assure that the huge financial investment, which is based on such assessments, can be successful. Efficacy and safety of products are the final goals of such developments. Therefore, Merck/Merck Serono implemented an additional specifically developed quality management system that covers all areas and locations in Merck Serono Research that were not yet regulated by an existing regulatory quality management system, e.g. GLP (Good Laboratory Practice). The system is known under the name Merck Serono Research-Quality Management System (MSR-QMS). Thus, we describe the implementation process of MSR-QMS as a research specific quality management system in a global company. Furthermore, the implementation process in one specific research department will be highlighted. Using a practical example, the validation of an analytical instrument in a MSR-QMS-regulated research laboratory will be shown and compared to a validation process in a strictly GLP-regulated area. A summary of the experiences with the new quality system will complete this article and the advantages of high quality research results in industry will be discussed.

Keywords: MSR-QMS (Merck Serono Research-quality management system); Optimizing of processes in research; Validation; IT lifecycle


A GUM-compliant uncertainty budget for the analysis of total carbon dioxide (TCO2) in equine plasma by D. Brynn Hibbert; Allen Stenhouse; Cary Murphy; Mark Jarrett; Roy Osborne; John H. Vine; Linda Glowacki; Charles Russo (pp. 523-530).
Samples of plasma from chosen horses are collected prior to racing for the analysis of total carbon dioxide (TCO2). Five or six (dependent on jurisdiction) tubes of blood are taken as required for a screen, followed (if positive) by confirmation (two tubes in quadruplicate) and, further confirmation (two tubes in quadruplicate) at a second referee laboratory. The threshold limit prescribed by the rules of racing is an amount concentration of 36.0 mM, with further action ensuing if the reported concentration is greater than 37.2 mM. Using QC data and an analysis of the measurement procedure, the combined standard measurement uncertainty of a measurement result was estimated to be 0.22 mM. This leads to a conclusion that the odds of incorrectly deciding that a sample at the threshold limit exceeded the action concentration, are 13 000 000:1 against. The combined standard measurement uncertainty could be reduced to 0.20 mM by combining results from the first and referee laboratories. An allowance for uncertainty of measurement of 1.0 mM is proposed, which leads to odds of 185 000:1 against concluding a sample is over the threshold limit when, in fact, it is not.

Keywords: Thoroughbred racing; Standardbred racing; Harness racing; TCO2 ; Equine plasma; Ion selective electrode; Compliance testing; Carbon dioxide analysis; Bicarbonate analysis; Measurement uncertainty budget; GUM


Improving the reliability of peak-evaluation results in gamma-ray spectrometry by Matjaž Korun; Tim Vidmar; Branko Vodenik (pp. 531-535).
In gamma-ray spectrometry the activities present in the samples are calculated from the areas of the peaks occurring in the spectra. Therefore, the utmost reliability of these input data must be maintained. To avoid systematic manual checks of the peak areas, the spectrum is analyzed consecutively by three peak-analysis programs. A comparative study was performed in which these peak-evaluation programs were tested to determine whether they yielded unbiased results. Only these programs can be used in a combined application. A consistency test of peak areas calculated by use of the three programs, for the same peak, was performed. Outlying results were discarded and the uncertainty of the best estimate for the area of a peak was calculated taking into account the dispersion of the peak-area results for this peak. The reliability of the computerized procedure has made manual checks of the peak areas unnecessary.

Keywords: Gamma-ray spectrometry; Peak-area analysis; Reliability of results; Uncertainties


Proposed guidelines for the final review of measurement results in the clinical laboratory by Xavier Fuentes-Arderiu; Montserrat Basart-Arraut; Àngels Bosch-Ferrer; María José Castiñeiras-Lacambra; Rosa López-Martínez; Jaume Miró-Balagué (pp. 537-542).
The standard ISO 15189 requires a systematic review of results of clinical laboratory examinations, but it does not provide details on how to carry out such a review. In this article, the Catalan Association of Clinical Laboratory Sciences proposes a guide for this review of patients’ clinical laboratory results pertaining to rational or difference scales (‘quantitative values’). The review process is based on the so-called plausibility control, which may be defined as the set of procedures used to decide if a measurement result is valid or not according to established clinical and biological criteria, considering four variables: (1) alert limits; (2) consistency with the previous result, if any; (3) consistency with other results obtained from the same sample, if any; and (4) consistency with the diagnosis (presumed or confirmed) or, when it is not known, the origin of the request, though these last criteria are generally very weak and the derived decisions may be scantly reliable.

Keywords: ISO 15189; Accreditation; Plausibility control; Validation of results
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