Accreditation and Quality Assurance最新文献

The globalisation of trade and environmental and health requirements, supported by the physical–chemical characterisation of relevant items, have promoted relevant evolutions on how test laboratories report results from their analysis. The relevance of reporting measurement results from the characterisation of these items with the measurement uncertainty is unquestionable to guarantee determinations are adequately uncertain and the objective interpretation of analytical information. The latest edition of the ISO/IEC 17025 standard, which supports the International Accreditation of test laboratories, even mentions the need to manage the impact of measurement uncertainty in the risk of false conformity assessments. Some accreditation bodies have considered this novelty and the reiteration that measurement results should be reported with the measurement uncertainty to make reporting the measurement uncertainty mandatory. This correct interpretation of the accreditation standard and society's expectations regarding the role of laboratories in the management of the most relevant interests of the community should be generalised.

The standards ISO/IEC 17025 [1] and ISO 15189 [2] both require laboratories to monitor their performance by comparison with results of other laboratories. But to what extent do laboratories have to participate. At what level and which frequency should a laboratory participate in PT schemes? To facilitate this question, a risk analysis approach should be applied by the laboratory. The EA (European co-operation for Accreditation) advisory document EA-4/18 (Guidance on the level and frequency of proficiency testing participation) [3] first published in June 2010 was revised in 2021 to include as one of the objectives, the concept of the risk analysis approach for PT participation. Risk analysis can be a nebulous concept so how can it be applied to PT participation? What criteria are important to take into consideration, can it be standardized, how do you train assessors to assess the suitability of a participation in PT strategy based on a risk analysis approach? To obtain feedback to such questions above, a survey was prepared and sent out to the EA accreditation bodies (Abs) to understand how this risk analysis approach is being implemented in their jurisdictions. In this survey, the following questions were posed:

• Are common risk-based principles used?

• What training is given to the assessors to ensure harmonization?

• What are the mains risks that are considered?

• At what frequency is the suitability of the laboratory’s risk-based approach (strategy) assessed?

This paper details the activities carried out by the Chemical Metrology Department of LATU in the development of a national proficiency testing (PT) scheme aimed at assessing the competence of laboratories in air quality parameters analysis. In this PT scheme, environmental monitoring laboratories were required to determine the concentration of elements in quartz-grade microfiber filters and impinger solutions, as well as to determine the amount fraction of a carbon monoxide in nitrogen gas mixture, within the range of (800 to 1700) µmol/mol. The focus of the present paper is mainly devoted to the second phase of the test, which addresses the preparation of the gas cylinder distributed to each participant for measurement. A detailed description of this stage is provided, along with the evaluation of the results reported by participating laboratories. This test provided an effective tool for participating laboratories to assess their national technical competence, using their preferred analysis methods.

Proficiency testing (PT) scheme for the mass fraction of arsenic (As), cadmium (Cd), copper (Cu), nickel (Ni) and zinc (Zn) in bottled drinking water matrices was conducted based on ISO/IEC 17043. The aim of the PT scheme was to evaluate laboratory capability in measuring minerals and contaminants in drinking water to comply with the implementation of Indonesian National Standard SNI 3553:2015 and the Regulation of Indonesia Minister of Health No. 492/2010. The PT material was a candidate of reference material, the homogeneity and stability testing on the material was performed and evaluated according to ISO 13528 and ISO Guide 35, and the material found sufficiently homogenous and stable during the transportation condition and PT period. Metrologically traceable reference values were used as the PT assigned values which were obtained using a high accuracy method, isotope dilution inductively coupled plasma mass spectrometry (ID ICP-MS) and gravimetric standard addition (GSA) with internal standard ICP-MS. The performance of the participants was evaluated mainly against the reference value based on z-scores and ζ-scores which is meaningful for assessing participants’ ability in measurement capabilities and measurement uncertainty evaluation. The PT results according to z-scores showed that more than 80 % of total 22 participants obtained satisfactory performance for Cu, Ni and Zn, while only 47 % and 58 % for As and Cd. The differences between the reference values and the robust mean of participants for As (21 %) and Cd (68 %) were found significant in the scheme which shown a big variability of measurement capability of Indonesian testing laboratories in this fields. Unsatisfactory performance of laboratories within their claimed uncertainty based on ζ-scores evaluation means that the laboratories may not assess accurately their measurement uncertainty. Therefore, re-assessment of their uncertainty estimation is needed, and the laboratories are encouraged to improve their capability in the measurement uncertainty for further enhancement.

Analytical quality by design (AQbD) is one of the risk-based approach used to develop robust analytical method in compliance with regulatory requirements. The concept of AQbD was recently established in the literature and has proven advantages in the pharma industries. Despite the differential view on AQbD, the International Council for Harmonization (ICH) has released the ICHQ14 document for analytical procedure development. Notably, the enhanced approach of the ICHQ14 document mimics AQbD workflows in analytical procedure development. Among ICHQ14 recommendations, the need for knowledge assessment, multivariate models for proven acceptable range (PARs) as method operable region, sample suitability assessment in robustness, and real-time release testing with product critical quality attribute specifications  as the challenging components for pharmaceutical industries. In addition, the integration of ICHQ14 with other ICH documents like ICH Q6A/6B, ICHQ8, ICHQ9, ICHQ10, ICHQ11, and ICHQ12 are well defined in the document. Thus, the revised ICHQ2 (R2) guideline has defined the validation procedure with integration to ICHQ14 documents.

Proficiency testing (PT) in chemical analysis ideally provides participants with feedback on all aspects of laboratory performance. In the field of analysis of elements in food, analyte levels in test items are often close to the legal limits. Performance criteria such as those in Commission Regulation (EC) No. 333/2007 also refer to maximum values for limits of detection (LOD) and limits of quantification (LOQ), as well as to selectivity and control of contamination. Therefore, PTs with analyte levels in the range of LOD and LOQ are also very beneficial, as at these low levels, insufficient selectivity or contamination during sample preparation are more likely to affect the analytical results.

Since 2017, our unit has provided 7 PTs, each with at least one parameter (e.g. an element prone to contamination such as arsenic or mercury) with very low mass fractions. In these cases, the datasets showed a significant proportion of results reported as “< LOQ”, together with quantitative results as well.

If the “< LOQ”-values are predominant, calculation according to ISO 13528 is not feasible. Due to the wide range of the individual LOQs, the numerical use of the LOQs or a percentage of them is not appropriate. Therefore, we decided to sort the quantitative results and the “< LOQ” results numerically. We then determined the median and evaluated all quantitative results above the median as “false positive”, while all other results were evaluated as “true statement”. In this way, laboratories affected by contamination, for example, received appropriate feedback.

The World Anti-doping Agency (WADA) International Standard for Laboratories (ISL), developed as part of the World Anti-Doping Program, requires satisfactory laboratory performance in the WADA External Quality Assessment Scheme (EQAS) in order to obtain and maintain WADA accreditation. Under this mandate, WADA regularly distributes urine and blood test samples to anti-doping laboratories to continuously monitor their proficiency. Over the years, WADA has employed classical, generic statistical methods, in accordance to ISO 13528, to evaluate quantitative EQAS results. Here, we set out the rationale for a modern statistical approach that recognizes and addresses the particular features of the measurement results typically obtained in such tests and present an approach involving Bayesian measurement models and statistical data analysis that is tailored specifically to anti-doping testing.

We report details of a proficiency testing (PT) scheme for laboratories undertaking the analysis of diesel engine particulates (DEP) collected on workplace air filter samples. Within this occupational hygiene setting, the established approach is to measure the elemental carbon (EC) content within DEP as a specific marker of workers’ exposure to engine emissions. Measuring EC is undertaken in laboratories using combustion-based analysers. To date six, PT rounds have been completed with participation ranging between thirteen and twenty-three laboratories. In each round participants received four quartz fibre filter samples (plus blank filters) loaded with DEP with indicative EC mass loadings in the range 9–204 µg/filter. Round assigned values and standard deviation for performance assessment values were calculated by consensus from returned participant data following outlier removal. On this basis, it was determined that on average 81 % of the returned data was deemed satisfactory, i.e. returning a z (or z’) score ≤ 2. The use of two operationally defined analytical protocols, namely NIOSH 5040 and EN 16909, now dominate but they give different EC values so the preparation of reference air filter samples with preordained EC values determined using both protocols for use in future interlaboratory comparisons is therefore recommended.

Soil certified reference material (CRM), UME EnvCRM 03 was produced by a collaborative approach among national metrology institutes, designated institutes and university research laboratories within the scope of the EMPIR project: Matrix Reference Materials for Environmental Analysis. This paper presents the sampling and processing methodology, homogeneity, stability, characterization campaign, the assignment of property values and their associated uncertainties in compliance with ISO 17034:2016. The material processing methodology involves blending a natural soil sample with a contaminated soil sample obtained by spiking elemental solutions for 8 elements (Cd, Co, Cu, Hg, Ni, Pb, Sb and Zn) to reach the level of warning risk monitoring values specified for metals and metalloids of soils in Europe. Comparative homogeneity and stability test data were obtained by two different institutes, ensuring the reliability and back up of the data. The certified values and associated expanded uncertainties for the total mass fractions of thirteen elements (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, V and Zn) are established. The developed CRM can be used for the development and validation of measurement procedures for the determination of the total mass fractions of elements in soil and also for quality control/assurance purposes. The developed CRM is the first example of a soil material originating from Türkiye.

Internal auditing is an important part of the ISO/IEC 17025:2017 standard. Clause 8.8 of the ISO/IEC 17025:2017 standard describes the requirements that the testing and calibration laboratories need to follow in the area of internal auditing. However, the standard does not describe which technique to use when conducting internal audits and the ISO 19011:2018 standard (Guidelines for Auditing Management Systems) only mentions the audit methods that can be used by an auditor, lacking practical aspects. Based on the internal auditing technique used, non-conformities that are present may or may not be detected. For example, technical competency of an analyst cannot be completely ascertained by just thoroughly reviewing the related documents such as training records. Therefore, it is important that internal auditors utilize appropriate techniques during an internal audit for it to be an effective one. Different internal auditors use different techniques during the audit. The commonest way internal auditors use is to develop a checklist (usually the one used by the accreditation body to which the laboratory is affiliated) for auditing the compliance to the ISO/IEC 17025:2017 management system and witnessing the technical competence of the technical staff. The aim of this article is to share the techniques utilized by the author during the internal auditing of ISO/IEC 17025:2017 accredited testing laboratories.