Certification of reference materials and accreditation of reference material producers: Questionable terminology leads to confusion

In the view of the Deutscher Kalibrierdienst (DKD) , a certifying body for reference materials can be considered to be a calibration laboratory. Therefore, accreditation of calibration laboratories in accordance with ISO/IEC 17025 is the most appropriate way to establish confidence in certificates for reference materials. If necessary, the criteria of ISO/IEC 17025 can be tailored to specific cases. There is no need to provide any new kind of reference-material specific accreditation. However, in view of the variety of reference materials and the practice existing in other countries, accreditation of testing laboratories and product certification bodies may optionally be acceptable as long as the same stringent principles with respect to traceability and measurement uncertainty are applied. Such accreditations but not accreditations of reference material producers (ISO Guide 34) are also covered by existing international mutual recognition arrangements (MRA).     

Accreditation of reference material producers: Let's get it right!

The accreditation of testing and calibration laboratories to ISO/IEC 17025 is increasingly calling for the accreditation of reference material (RM) producers. Two international guides, ISO Guide 34 (2000) " General requirements for the competence of reference material producers" issued by the ISO Committee on Reference Materials and ILAC-G 12 " Guidelines for the requirements for the competence of reference material producers" issued by the International Laboratory Accreditation Cooperation (ILAC), are already in use for this purpose. Recently however initiatives have been launched to accredit RM producers to ISO 17025 as calibration laboratories and it has been suggested that a combination of ISO/IEC 17025 " General requirements for the competence of testing and calibration laboratories" and ISO Guide 34 may be the best option. This publication is an expression of the position of the ISO Committee on Reference Materials (ISO/REMCO) on the standards and guides currently in use in the accreditation of RM producers. The paper discusses the advantages and disadvantages of these standards and guides from the perspective of benefit to RM producers and RM users. In conclusion, the use of ISO Guide 34 alone or in combination with ILAC-G 12 is the preferred system for the accreditation of RM producers. Therefore ISO/REMCO strongly encourages all accreditation bodies to adopt ISO Guide 34.     

The Japanese traceability system and the role of uncertainty evaluation in measurement

 The new traceability system of measurement standards based on the Japanese Measurement Law has been established since November 1993. Some reference materials such as metal standard solutions, pH standard solutions and standard gas mixtures are included in the system together with relevant physical quantities. In this system, primary measurement standard instruments or primary reference materials are designated by the regulation for each quantity. For the practical dissemination of each quantity, accreditation of calibration bodies is recognized by the steering committee under the supervision of the government. In the course of assessment of a candidate calibration body, the concepts of ISO/IEC Guide 25 and ISO/IEC Guide 58 are effectively introduced. For the estimation of reliability, the concept of how to introduce the statistical approach is effectively considered. The method of uncertainty evaluation described in the ISO document entitled "Guide to the expression of uncertainty in measurement" is adopted.     

The development of a National Accreditation System in South and Southern Africa

 In South African industry there is a strong appreciation of Quality Assurance. More than 1400 companies have been certified as complying with ISO 9000, and this, of course, has resulted in a strong demand for accredited calibration and test facilities. Work on the development of a national calibration service started in 1976, and the South African National Calibration Service (SANCS) was inaugurated in 1980 with 13 calibration laboratories. The early maturity of the SANCS can be judged by the fact that by 1984 it had the technical capability to establish a mutual recognition agreement with a European country. It now has a total of some 191 accredited laboratories, 139 calibration laboratories and 52 testing laboratories. In 1993, the SANCS signed mutual recognition agreements with the CNLA (Taiwan) and the European Co-operation for the Accreditation of Laboratories (EAL). In 1994 it entered the field of testing laboratory accreditation and is already experiencing a strong influence therefrom, and in 1997 it changed its name to National Laboratory Accreditation Service (NLA). In May 1995, the NLA was appointed by the Department of Trade and Industry to establish a South African National Accreditation System (SANAS). Progress with this work up to the present time has been substantial.     

Use of ISO Guides 25, 30, 31, 34, 35, and 9001 in re-engineering Bethlehem Steel Corporation's analytical chemistry reference materials program

 Many certified reference materials are needed to calibrate and control analytical measurement processes in integrated steel works. It is beyond the scope and capacity of most national laboratories to supply all of these needs. Yet, the demand for these materials is steadily increasing as more steel producers update their quality systems in preparation for ISO 9000 registration and/or ISO Guide 25 laboratory accreditation assessments. This paper describes how the Bethlehem Steel Corporation updated its reference materials program to meet its internal needs and offers a model for use by others in improving their programs. Received: 22 April 1998 · Accepted: 12 May 1998     

Assuring the reliability of mass spectrometry for the routine determination of traces of doping in horse-urine

Summary This paper describes an analytical method using a nuclear-related technique for the detection of forbidden doping substances in the urine of race horses. The proposed method, adapted from the Méthode Alcaline Sur C-18 developed by the French Laboratoire de Contr?le Antidopage, is based on gas chromatography separation followed by mass spectrometry (GC-MS). The method was validated for caffeine, identified as the most frequent doping substance in the Brazilian horseracing activity. This validation is also a major requirement to achieve ISO/IEC 17025 laboratory accreditation. The validation has led to several metrological challenges because the decisions are largely based on qualitative results (“false-positive” and/or “false-negative”) and the degree of accuracy, as well as the traceability had to be determined in the absence of certified matrix reference materials.     

Accreditation of reference material producers: an Australian perspective

The National Association of Testing Authorities, Australia has operated an accreditation program for reference material producers since 1997 with accreditation now being offered to ISO Guide 34 (2000). This paper discusses the benefits and disadvantages to both the producers and the users of reference materials (testing laboratories) and their clients of a formal system of third-party accreditation of reference material producers. The merits of using ISO Guide 34 (2000) rather than ISO/IEC 17025 as the core standard in the accreditation process are discussed.     

Can the new ISO Guide 25/EN 45001 create better confidence in laboratory operations?

 Confidence in laboratory operations is discussed based on the ongoing revision of the ISO/IEC Guide 25. Confidence is a subjective attribute, which also depends on whose interest is considered. New and better-defined quality systems and technical elements will be included, and these are beneficial to the transparency of laboratory operations, as well as to the accreditation process. The ultimate aim is, of course, to satisfy customers. The testing laboratories' industrial customers are, however, generally unfamiliar with the ISO/IEC Guide 25 and accreditation. The main reason for improved confidence in testing and calibration laboratories is foreseen to come from closer interaction between laboratories and their customers.     

Reference material requirements for laboratories and the role of accreditation bodies

It is now over two years since ISO/IEC 17025 General requirements for the competence of testing and calibration laboratories was published. The standard places increased emphasis on the demonstration of traceability of measurements made by laboratories. In the areas of chemical and biological metrology, the introduction of this standard has brought new challenges for laboratories to grapple with. This paper will examine the requirements regarding traceability for chemical and biological measurements, with specific reference to the use of reference materials by laboratories. This will be explored from the perspective of both accreditation bodies and a laboratory which is both a user and producer of certified reference materials. Moreover, the paper will describe mechanisms that are being used to improve the use of reference materials by accredited laboratories and hence the traceability of measurements. Finally the role of accreditation programs for reference material producers in assisting with this aspect will be examined.Electronic Supplementary Material Supplementary material is available for this article if you access the article at . A link in the frame on the left on that page takes you directly to the supplementary material.Presented at BERM-9—Ninth International Symposium on Biological and Environmental Reference Materials, June 15–19, 2003 Berlin, Germany.     

Conformity assessment and metrology: update on the state of affairs

A couple of years ago, ISO CASCO launched a major project of transforming all the existing ISO Guides on conformity assessment to a comprehensive series of ISO standards 17000 being now in various stages of development. As the concept of traceability underpinning all measurements has been a basic mission of metrology, a number of these standards have a direct bearing on metrology. The series is logically based on a definition standard, ISO 17000, giving, among others, a guidance which activities fall under conformity assessment. The fact that calibration does not, might have important consequences which must yet be assessed. A controversial discussion on some issues has been in progress concerning ISO 17011 on accreditation bodies which touches both on national metrology institutes (NMIs) with an accreditation function and on calibration labs at large. ISO 17040 on peer review could be used with an advantage to support mutual recognition arrangements among a limited number of bodies of a specialized expertise (e.g., CIPM MRA among NMIs under the Metre Convention). ISO 17025 has been the most important standard for the metrology community and has undergone a major overhaul taking on board the uncovered requirements from ISO 9001:2000. In general, the paper will give an update on the developments outlined above and discuss the consequences and further steps from the viewpoint of metrology.     

The third edition of ISO Guide 34: what were the drivers for the revision and what is new?

After the International Laboratory Accreditation Cooperation (ILAC) had taken in 2004, the resolution to conduct accreditation of producers of reference materials according to ISO Guide 34 ‘General requirements for the competence of reference material producers’ in combination with ISO/IEC 17025 ‘General requirements for the competence of testing and calibration laboratories’, ISO/REMCO, the ISO Committee on Reference Materials, decided in 2005 to revise ISO Guide 34 to align it closer with ISO/IEC 17025 and to clarify certain issues for accreditors and producers seeking accreditation without adding new requirements. Moreover, the publication in 2007 of ISO/IEC Guide 99 ‘International vocabulary of metrology—Basic and general concepts and associated terms (VIM)’ triggered additional adaptations of the guide.     

Can single-operator laboratories comply with all of the requirements of ISO/IEC 17025:2005?

ISO/IEC 17025:2005 states that its requirements are “applicable to all laboratories regardless of the number of personnel” and would therefore include single-operator laboratories. However, there are reservations as to whether these laboratories can comply with all of the requirements without jeopardizing independence of judgement and impartiality. Similarly, there are some requirements of ISO/IEC 17025:2005 including staff supervision, internal communication processes and appointment of deputies that are considered unlikely to apply to a single-operator laboratory. The ISO/IEC 17025:2005 is widely used as the international standard of quality assurance by which accreditation bodies assess the competency of testing and calibration laboratories. There does, however, appear to exist, disagreement amongst accreditation experts when considering single-operator laboratories. Some accreditation bodies accredit single-operator laboratories, whilst others require additional human resources prior to granting accreditation. This discrepancy leads to unfair competition amongst laboratories as a single-operator laboratory by definition needs less resources (both human and financial) to achieve and maintain accreditation, compared with a laboratory where additional human resources need to be sought prior to and in order to maintain accreditation. The ISO/IEC 17025:2005 is in the process of being revised, and this is an opportune moment to address the issues aforementioned with the aim of removing ambiguity and enhancing clarity. In addition, the hope is to assist the accreditation bodies themselves to adopt a consensus approach when granting accreditation towards single-operator laboratories.     

Metrological traceability in laboratory medicine

 The establishment of a reference examination system necessary for metrological traceability of the many types of sophisticated examination result in laboratory medicine is a daunting task, which has been made mandatory by the EU Directive on in vitro diagnostic medical devices and the requirements for accreditation. Following a definition of examinand and allowed examination uncertainty, a dedicated calibration hierarchy is established from stated reference through alternating reference examination procedures and calibrators providing a traceability chain from examination result to the reference, often a definition of a measurement unit. The various types of possible calibration hierarchy are outlined in EN ISO Standards. Recent efforts by national and international stakeholders to establish a global reference examination system have led to the creation of a Joint Committee on Traceability in Laboratory Medicine with the International Committee for Weights and Measures, International Bureau of Weights and Measures, International Federation of Clinical Chemistry and Laboratory Medicine, International Laboratory Accreditation Cooperation, and World Health Organization as the principal promoters. This structure will identify reference procedures, reference materials, and reference laboratories, and seek support for further prioritised and coordinated development of the system. Received: 1 August 2002 Accepted: 22 November 2002 Based on a lecture at an IUPAC Seminar, EC JRC Institute for Reference Materials and Measurements, Geel, BE, 2001–12–18 Correspondence to R. Dybkaer     

Laboratory authorization versus accreditation in transitional economies: case study of Serbia

Many CEE governments are still using various systems of laboratory authorization together with ISO/IEC 17025 laboratory accreditation. It is difficult to understand from the EU prospective, the existence of two parallel laboratory competence verification systems. The basic relations between laboratory accreditation and authorization: independence and succession have been defined. The case study of testing laboratory accreditation versus authorization in Serbia, has been presented and discussed. Relevant requests and procedures for water quality, food and air quality testing laboratory authorization were analysed in detail. Comparative analyses of accreditation and authorization have established: (i) independent relations, (ii) relevant regulation is in collision and barely legal, (iii) authorization is (technically) on the far lower level than accreditation is, and (iv) authorization requests cause high space and personnel costs. It has been concluded that it is not adequate to perform two policies at the same time: one EU oriented—laboratory accreditation, and one non-EU oriented—laboratory authorization. The policy proposal is that all CEE countries should abandon existing laboratory authorization procedures and replace them by accreditation. Proposed goal could be reached in rather a short transition process of 2–3 years.     

Interlaboratory comparison for the determination of pesticide residues in Chinese cabbage

The results of and findings from an interlaboratory comparison among laboratories carrying out food testing of pesticide residues in the APEC (Asia–Pacific Economic Cooperation) region are presented and discussed to show critical roles of chemical metrology infrastructure in establishing traceability of measurements and in supporting existing measurement capability in safety and quality of food trade. The study material, which was prepared and certified by Korea Research Institute of Standards and Science (KRISS), was freeze-dried Chinese cabbage powder fortified with two organophosphorous pesticides (diazinon and chlorpyrifos). Among 14 participants, 12 laboratories were accredited based on ISO/IEC17025 and one laboratory was under assessment for the accreditation at the time of this study. Though all participants demonstrated very good intra-day repeatability and inter-day intermediate precision, many of them showed a large bias from the certified values. It is suggested that in addition to the accreditation system, economies are encouraged to develop appropriate chemical metrology infrastructure, which could effectively support laboratories to assure measurement traceability to SI, for which NMIs could play significant roles through their metrological services recognized in Mutual Recognition Arrangement (MRA) of the International Committee for Weights and Measures (Comité International des Poids et Mesures, CIPM).     

Estimation of measurement uncertainty in food microbiology: The ISO approach

Given the current interest in measurement uncertainty (MU) in food microbiology, in particular for laboratory accreditation purposes, and the need to have harmonized reference documents specifically in that area at the international level, ISO is conducting works to meet this need. An ISO Technical Specification (ISO/TS 19036) is being prepared on MU estimation for quantitative determinations. A global approach has been chosen, based on the reproducibility standard deviation of the final result of the measurement process. Three possibilities are envisaged for the estimation of the reproducibility standard deviation, in a decreasing order of preference: The intra-laboratory standard deviation, the inter-laboratory standard deviation derived from method validation, and the inter-laboratory standard deviation derived from proficiency testing.The uncertainty of qualitative determinations is still under investigation, and will be covered by a separate ISO publication. Presented at AOAC Europe/Eurachem Symposium March 2005, Brussels, Belgium     

Laboratory accreditation: The operation of an established scheme

NAMAS, the National Measurement Accreditation Service, was formed in 1985 and has currently accredited some 1050 testing and calibration laboratories in the United Kingdom. NAMAS is managed by an Executive of 60 staff which is based at the National Physical Laboratory, one the UK's largest Government Research Establishments. Laboratories seeking accreditation are assessed by fully trained technical experts contracted by NAMAS, against the criteria set out in the NAMAS Accreditation Standard M10; the criteria contained in this document are fully consistent with the international standards for laboratory accreditation EN 45001 and ISO Guide 25. NAMAS has recently published a document which provides guidance on the interpretation of the NAMAS Accreditation Standard for analytical laboratories. Assessment involves a consultative preassessment visit which is followed by a thorough on-site assessment of a laboratory's quality system and testing activities by a team of expert assessors. Following the correction of any noncompliances found at the assessment, the laboratory receives a certificate of accreditation and a schedule which defines those tests and analyses for which the laboratory is accredited. NAMAS has negotiated a number of mutual recognition agreements with similar accreditation bodies in other countries and negotiations with other schemes are underway. The imminent approach of the European Single Market has highlighted the need for independent third party assurance of testing and calibration and this should ensure the continued growth of NAMAS and similar schemes elsewhere in Europe.     

Nuclear forensics—metrological basis for legal defensibility

The admissibility of nuclear forensics measurements and opinions derived from them in US Federal and State courts are based on criteria established by the US Supreme Court in the case of Daubert v. Merrell Dow and the 2000 Amendment of Rule 702 of the Federal Rules of Evidence. These criteria are being addressed by new efforts that include the development of certified reference materials (CRMs) to provide the basis for analytical method development, optimization, calibration, validation, quality control, testing, readiness, and declaration of measurement uncertainties. Quality data is crucial for all stages of the program, from R&D, and database development, to actual casework. Weakness at any point in the program can propagate to reduce the confidence of final conclusions. The new certified reference materials will provide the necessary means to demonstrate a high level of metrological rigor for nuclear forensics evidence and will form a foundation for legally defensible nuclear chemical analysis. The CRMs will allow scientists to devise validated analytical methods, which can be corroborated by independent analytical laboratories. CRMs are required for ISO accreditation of many different analytical techniques which may be employed in the analysis of interdicted nuclear materials.     

Revision of ISO guide 25

 ISO/IEC guide 25 is the internationally recognised base document for the accreditation of laboratories. Laboratory accreditation is a system of peer assessment and a formal recognition that a laboratory is competent to perform specific tests or types of tests ISO/IEC guide 25 plays a fundamental role in the life of the analytical chemist and is pivotal to the acceptance of the philosophy "once tested everywhere accepted" and to ensuring the mutual acceptance of test data. Within the EU, the attainment of accreditation to ISO/IEC guide 25 has become a way of life and it is now mandatory for laboratories engaged in certain regulatory work areas. Guide 25 is currently under revision and over the past 2 years or so it has been the subject of much debate among the calibration and testing community and it has engendered a considerable amount of written and oral comments. The latest revision entitled "Draft International Standard ISO/IEC DIS 17025: General Requirements for the Competence of Testing and Calibration Laboratories" was circulated to national standard organisations for their "comment and approval" in mid 1998. Voting on this document commenced on 9 July and terminates on 9 December 1998. It is anticipated that a final draft could be circulated in 1999. In accordance with the Vienna agreement this is a parallel ISO/CEN enquiry. This paper will discuss the implications of the technical requirements of the current document for analytical chemistry with particular emphasis on, the strengths, weaknesses and deficits inherent in the draft circulated in July 1998.     

Performance evaluation for proficiency testing with a limited number of participants

Proficiency testing (PT) is an essential tool for laboratories to assess their competency. Also, participation in PT has become one of the mandatory requirements for laboratory to seek accreditation according to ISO/IEC 17025. For this reason, the effectiveness of performance evaluation by PT scheme is of great concern for the participants and for accreditation bodies as well. In practice, owing to unavailability of other appropriate alternatives, PT scheme providers may have to choose using consensus values to evaluate the performance of participants. However, such consensus values approach was not recommended by relevant international guidelines for PT schemes with limited number of participants. With the use of Monte Carlo simulation technique, this study attempted to investigate the effectiveness of using consensus values for performance evaluation in PT schemes with limited number of participants. The simulation process was schemed according to the statistical model provided by ISO 5725-1 for laboratory measurement results, which covered components like method bias, laboratory bias, and measurement precision. The effectiveness of the consensus value approach was expressed as the percentage of participants in a simulation run could get the same evaluation result, either satisfactory or unsatisfactory, against the “true value.” The findings indicated that the number of participants, choice of consensus values, mass fraction of analyte, method bias, laboratory bias, and measurement repeatability of participating laboratories would all affect the effectiveness of the consensus value approach but at different extent. However, under certain circumstances, use of consensus value could still be considered as an acceptable approach for performance evaluation even the number of participants was limited. Some of the findings were further verified using real data from PT schemes where appropriate certified reference materials or reliable reference values were available.