International Laboratory Accreditation Cooperation Research Articles

Uncertainty Assessment in Temperature Uniformity Survey of Thermal Processing Equipment According to AMS2750 Aerospace Specification

Thermal processing equipment used in the aerospace industry must meet the requirements of the processes for which they are intended. The periodic tests performed by calibration laboratories, according to the AMS2750 specification, are intended to ensure compliance with these equipment requirements. While this specification does not explicitly state the need for uncertainty calculation, it does specify that pyrometry laboratories must have an ISO/IEC 17025 Quality System accredited by a recognized regional body which is a member of the International Laboratory Accreditation Cooperation (ILAC). Therefore, the calculation of uncertainties is necessary. This work presents a methodology for conducting temperature uniformity surveys and uncertainty assessment in these tests. This methodology has been applied to four different types of equipment to analyse, in each case, the contributions of uncertainties and to assess their potential for improvement. The objectives that laboratories should aim for include improving measurement accuracy and reducing uncertainty components in order to meet the criteria of both AMS2750 and ISO/IEC 17025.

How Do Accreditation Bodies Manage Risk Associated with the Accreditation Business?

Among other factors, accreditation-focused entities operating various accreditation schemes for conformity assessment bodies are expected to fulfill requirements of international standard ISO/IEC 17011:2017 (Conformity Assessment – Requirements for accreditation bodies providing conformity assessment). Consideration should be made of legal requirements. Additional requirements of the International Accreditation Forum (IAF) and International Laboratory Accreditation Cooperation (ILAC) as well as the requirements of scheme owners, such as CORSIA and GlobalG.A.P., etc., should adhere to the word “risk,” which appears in different places of the ISO/IEC 17011:2017. The main objective of ISO/IEC 17011:2017 is to ensure competence, consistent operation, and impartiality of accreditation bodies accrediting conformity assessment bodies. The term “risk” is defined as the “effect of uncertainty on objectives” (ISO 31000:2018, clause 3.1). Therefore, it is required to consider all possible uncertainties by accreditation bodies (ABs) and initiate suitable actions to prevent or mitigate such risks. Mandatory documents (MDs) published by the International Accreditation Forum (IAF) have addressed how accreditation bodies should consider risks when they operate specific accreditation schemes, such as EMS, FSMS, QMS, OH&SMS, etc. There are no common viewpoints published or discussed in relation to the risks associated with accreditation bodies. This aims to create awareness of possible risks associated with accreditation bodies and share experiences with examples of cases on how accreditation bodies react to uncertain situations with respect to achieving the intended objectives of ISO/IEC 17011.

The Need for Standards Unification in Forensic Laboratory Practices: Protocol for Setting Up the Arab Forensic Laboratories Accreditation Center.

Background Despite the recent trend toward developing and applying quality control measures in the forensic science disciplines, there is a heightened interest to efforts to ameliorate disparate quality among laboratories through the enforcement of standards and best practices.Objective This protocol aims to set up the Arab Forensic Laboratories Accreditation Center (AFLAC) to act as a key driving legal force for accreditation of the different forensic laboratories in the Arab region.Methods Upon its development, the Forensic Laboratory-Arabian Gate (FLAG) platform will serve as a preliminary stage for the AFLAC, and 2 preparatory steps will be achieved through the FLAG platform: the first one is a scoping study to analyze the international guidelines regarding the forensic laboratory practices in different specialties, and the second one is mapping surveys to explore how the international and national guidelines are translated into practice in Arab forensic laboratories. Development of the Arab forensic laboratories accreditation center will be initiated by building the AFLAC quality management system, which comprises formation of the forensic science committees to achieve the standards required for accreditation in each discipline. This will be followed by the attainment of regional accreditation recognition of the Arab Accreditation Cooperation (ARAC) and the International Laboratory Accreditation Cooperation. This recognition necessitates achieving International Organization for Standardization/International Electrotechnical Commission 17011 standard requirements prior to official application to the ARAC.Results The first phase of our work (the FLAG platform) began in February 2022 and is expected to end in December 2022. The FLAG platform was proposed to the Arab Society of Forensic Sciences and Forensic Medicine in March 2022, and we received approval to host this web development project. Subsequent phases are anticipated to begin in January 2023 and are expected to end in 2025.Conclusions This work describes our approach to provide a valuable tool for forensic laboratory accreditation services to promote the best practice and its consistency in the field of forensic sciences in the Arab region.International Registered Report Identifier (IRRID)PRR1-10.2196/36778

Application of systems thinking to the establishment of metrological traceability chains

International agreements in the field of metrology and accreditation of calibration laboratories are the basis for establishing global metrological traceability. Important elements of metrological traceability are calibration of measurement standards and measuring instruments, assessment of measurement uncertainty. The International Laboratory Accreditation Cooperation has a specific policy regarding on traceability of measurement results and estimation of measurement uncertainty in calibration.
 The partial concept diagram around metrological traceability in accordance with the International Vocabulary of Metrology is proposed. This diagram contains a total of nine metrological concepts, which have most of the associative relations. There are associative relations between the concept of metrological traceability chain and concepts of metrological traceability, measurement standard, calibration and calibration hierarchy, and through the concept of measurement standard with the concept of measurement uncertainty.
 Systems thinking to the analysis of state of proposed terminological system around metrological traceability was applied. For construction of generalized metrological traceability chain, all the established properties of the system elements around the terminology system of metrological traceability were taken into account.
 Generalized metrological traceability chain for different levels of the calibration hierarchy was proposed. The proposed chain can be used to develop appropriate chains for specific areas of measurement. To achieve this, it is necessary to determine the specific measured value, the required measurement uncertainty for different levels of the calibration hierarchy and select the necessary measurement standards. Such schemes should be used in national metrology institutes and calibration laboratories.

An assessment of the impact of Brazilian energy efficiency policies for electric motors

The three-phase induction motor was the fundamental component for productivity and growth in the second industrial revolution in Europe and the United States in the late nineteenth century. Presently, it is the main charge in electrical systems on a global level. In Brazil, it reaches more than 65% of total electricity consumption. Policies were established on the minimum efficiency level of the three-phase induction motor to improve energy efficiency in the Brazilian electrical system. The Brazilian legislation for the performance of electric motors is recent because the first document was issued in 2002. Based on the policies on the performance improvement of motors, what were the changes that occurred in the three-phase induction motors with the squirrel-cage rotors marketed in Brazil? Therefore, this study evaluated the performance of 435 motors tested between 2015 and 2016, with powers between 1 HP and 250 HP for four normalized speeds based on three laws of electric motor performance: Presidential Decree No. 4,508/2002; Interministerial Ordinance No. 553/2005 and Interministerial Ordinance No. 1/2017. All data were collected via standardized laboratory tests accredited by the National Institute of Metrology, Standardization, and Industrial Quality (INMETRO) and the International Laboratory Accreditation Cooperation (ILAC). The results show that 97% of the tested motors have higher performances than Decree No. 4,508/2002. Relatedly. 64% have higher performances compared to what is stipulated by Ordinance 553/2005. Also, only 21% have higher performances compared to what is stipulated by Ordinance 1/2017.

The role of SSDL in quality assurance in radiotherapy

This paper describes the role of the Polish Secondary Standard Dosimetry Laboratory (SSDL) in quality assurance in radiotherapy by means of providing calibration of ionisation chambers, TLD postal dosimetry audits and end-to-end audits for radiation therapy. A historical review of the methods and results are presented. The influence of the SSDL in Warsaw on radiation protection of patients in Poland is discussed. The International Atomic Energy Agency together with World Health Organisation (IAEA/WHO), through its network of SSDLs around the world, propagates newly developed methods for calibration and auditing. Suitable high quality equipment was provided by the IAEA, as well as special materials and technical support to the SSDL in Warsaw. The activity of the SSDL and the services provided for Polish radiotherapy centres have resulted in a reduction of discrepancies between planned doses and doses delivered to patients. The newly tested IAEA methods of end-to-end on-site dosimetry audits allow for monitoring and improving the quality of IMRT in Poland. The traceability of standards used for the calibration of therapy level dosimeters from Polish radiotherapy centres is assured by the IAEA dosimetry laboratory. The consistency of methods performed in the Polish SSDL with the ISO:17025 norm is supervised by the Polish Centre for Accreditation - a member of International Laboratory Accreditation Cooperation (ILAC), for calibration and testing. Due to the rapid technological development of radiotherapy, special attention has to be paid to newly developed methods for dosimetry auditing and institutions which provide services for assuring radiation safety of patients.

European current landscape in laboratory accreditation

The number of accredited laboratories in the world shown considerable growth in the last 2 decades. These laboratories are from different institutions, such as national or multinational organizations, Higher Education Institutions (HEI) and Research Institutes (RI). This paper presents and comments on the current landscape of accreditation, from the point of view of testing and calibration laboratories under the ISO/IEC 17025 standard, in Europe. Laboratories accredited by signatory bodies of the International Laboratory Accreditation Cooperation Mutual Recognition Arrangement (ILAC MRA) were identified and classified by institution type. The results were compared with those obtained in a previous research on the American Continent. An upward trend in the number of accredited laboratories with the increase in the population and/or GDP was observed in EU countries. Several similar characteristics were found in both regions, America and Europe. Nevertheless, a strong regulation in specifics areas seems to be higher in Europe and a smaller disparity was observed between European countries. Besides, as accreditation of laboratories in HEI and RI presents additional difficulties, the identification of these laboratories will be used as a basis for future work.

On the Calibration of GNSS-Based Vehicle Speed Meters†.

Thanks to their metrological characteristics (accuracy, dimensions, synchronization capability, easy interfacing, and so on), in the last few years, the GNSS (Global Navigation Satellite System) based speed instruments are often used in a wide field of application. The traceability of the measurement results achieved by the GNSS instrument should be made by means of calibration procedures in compliance with the ISO/IEC 17025 standard and ILAC (International Laboratory Accreditation Cooperation) policy on the traceability of measurement results. In this context, some calibration methodologies have been proposed in the literature or used by some calibration centers. In a speed range from 1 to 300 km/h, an analysis on the suitability of the experimental calibration method (based on a couple of photocells placed on the road at a certain distance) for the GNSS speed measurement systems is presented in this paper. An analysis of the measurement setup has allowed for the recognition of both all the uncertainty contributions and defines the variability range of their values. After the formulation of the relationships between the uncertainty contributions and the total calibration uncertainty due to the calibration method, the sensitivity analysis has been made. The analyzed measurement setup, even if considering a careful choice of both instrumentations and methodologies, is suitable for the calibration of high accuracy GNSS based instruments only considering distances between the photocells sufficiently large and for speed values lower than 200 km/h. In any case, the proposed analysis can be a useful tool to allow for the choices on the measurement setup to reach the desired trade-off between calibration costs and compliance with technical requirements and also the calibration of instrumentation different by GNSS.

Certified Reference Materials and Metrological Traceability for Mycotoxin Analysis

Abstract In the past decade, with the signing of the joint declaration by the International Bureau of Weights and Measures (BIPM), the International Organisation of Legal Metrology, the International Laboratory Accreditation Cooperation, and the International Organization for Standardization, and the issuing of new international standards such as ISO/IEC 17025 and ISO 13528, metrological traceability has become more and more important for the mutual recognition of measurement results. It is found that the important factors for ensuring the accuracy of results are not only relevant to calibrants but also to the analysis procedure. This paper focuses on the analysis of key factors that affect measurement results, such as analytical methods, reference materials (RMs), and proficiency testing of mycotoxins. The Capacity Building and Knowledge Transfer Programme for mycotoxins, led by the BIPM, which aims to establish a global measurement system traced to the Système International d’Unités (SI), is well illustrated. Furthermore, this paper suggests to stakeholders that great effort is needed to promote the effective use of certified RM resources that are traced to the SI and globally recognized by the International Committee for Weights and Measures to finally realize “one measurement, global recognition.”

Certified Reference Materials and Metrological Traceability for Mycotoxin Analysis.

In the past decade, with the signing of the joint declaration by the International Bureau of Weights and Measures (BIPM), the International Organisation of Legal Metrology, the International Laboratory Accreditation Cooperation, and the International Organization for Standardization, and the issuing of new international standards such as ISO/IEC 17025 and ISO 13528, metrological traceability has become more and more important for the mutual recognition of measurement results. It is found that the important factors for ensuring the accuracy of results are not only relevant to calibrants but also to the analysis procedure. This paper focuses on the analysis of key factors that affect measurement results, such as analytical methods, reference materials (RMs), and proficiency testing of mycotoxins. The Capacity Building and Knowledge Transfer Programme for mycotoxins, led by the BIPM, which aims to establish a global measurement system traced to the Système International d'Unités (SI), is well illustrated. Furthermore, this paper suggests to stakeholders that great effort is needed to promote the effective use of certified RM resources that are traced to the SI and globally recognized by the International Committee for Weights and Measures to finally realize "one measurement, global recognition."

RusAccreditation and International Recognition of the National Accreditation System

The activities of the Federal Accreditation Service including cooperation with international accreditation institutions, i.e., International Laboratory Accreditation Cooperation (ILAC) and the Asia-Pacific Laboratory Accreditation Cooperation (APLAC) are reviewed. Issues regarding implementation of the system of good laboratory practice in the context of cooperation between Russia, Organization for Economic Cooperation and Development (OECD), and Slovak National Accreditation Service are considered. Information about mutual recognition agreements and bilateral arrangements of the Federal Service for Accreditation and national accreditation bodies of the foreign countries are discussed along with the results of the activities of RusAccreditation during the 1st quarter of 2018 and goals for the near future.

Current American landscape in laboratory accreditation according to ISO/IEC 17025

The number of laboratories worldwide seeking accreditation has increased considerably in the last years. These laboratories are from different institutions, some of them higher education institutions (HEIs) and research institutes. The aim of this work is to present the current landscape of accreditation of testing and calibration laboratories, according to ISO/IEC 17025 standard, in the American Continent (North, Central and South America). Data on accredited laboratories were taken from the Web sites of accreditation bodies signatories to the International Laboratory Accreditation Cooperation Mutual Recognition Arrangement. The accredited laboratories were classified by institution type. Countries with a high number of accredited HEI laboratories were identified, as well as a correlation between gross domestic product and total number of accredited laboratories. North American countries have the highest total numbers of accredited laboratories, except for Brazil in South America. This survey highlights strategies and activities adopted in some countries that resulted in high number of accredited HEI laboratories.

SMIIC Forum 2012

Organized by the Standards and Metrology Institute for Islamic Countries(SMIIC), a subsidiary organ of the Organization of Islamic Cooperation(OIC), this forum was held on November 6-9, 2012, at Turkey’s Cornelia DeLuxe Resort in Belek. The 160 delegates, who came from thirty-five countries,represented the National Standardisation Bodies (NSB), important nationalorganizations of member countries, and such international organizationsas the International Organisation for Standardisation (ISO), the InternationalElectrotechnical Commission (IEC), the European Committee forElectrotechnical Standardisation (CENELEC), the Standardisation Organisationfor the Cooperation Council for the Arab States of the Gulf (GSO),the Turkish Standards Institution (TSE), the Turkish Accreditation Agency(TURKAK), the Saudi Standards Metrology and Quality Organization(SASO), the Malaysian National Metrology Laboratory (SIRIM), the InternationalLaboratory Accreditation Cooperation (ILAC), the OIC GeneralSecretariat, the Commercial Cooperation of the Organization of Islamic Cooperation(COMCEC), the Statistical Economic and Social Research andTraining Centre (SESRIC), and the Islamic Centre for the Development ofTrade (ICDT).Also present were media outlets, representatives of various governmentbodies, officers from the Presidency of Religious Affairs of the Republic ofTurkey (DIYANET), and academics from significant international universities.One of the forum’s main objectives was to create a platform to bring togetherexperts and professionals from the fields of standardization, accreditation, andmetrology in order to discuss these areas’ current circumstances within OICmember countries and at the international level ...

PT community meet in Istanbul: proficiency testing workshop

The historic city of Istanbul, known for where the East meets the West, became the meeting place for the global proficiency testing (PT) and external quality assurance (EQA) community for 4 days in October 2011. This was the 7th international PT workshop on Proficiency Testing in Analytical Chemistry, Microbiology and Laboratory Medicine organized by the EURACHEM Proficiency Testing Working Group in association with EQALM and CITAC. The workshop was supported locally by several Turkish organizations including the Middle East Technical University (METU), the Petroleum Research Center, EURACHEM-Turkiye, TUBITAK UME and TURKAK. The wonderful setting on the coast of the Sea of Marmara provided the perfect location for this successful workshop which once again provided an excellent opportunity for providers, users and regulators of PT/EQA to come together to discuss a wide range of key issues across the three disciplines of analytical chemistry, microbiology and laboratory medicine. The 233 delegates attending from 54 different counties ensured a truly global perspective. Since the last (6th) PT workshop held in Rome during October 2008, there have been a number of developments in the field of proficiency testing, one of the most notable being the publication of ISO/IEC 17043, the new international standard for the competence of PT/EQA providers, addressing the requirements for the development and operation of PT/EQA schemes. This new standard has been adopted by the International Laboratory Accreditation Cooperation (ILAC) as the requirements against which PT/ EQA providers should be accredited. With the publication and its subsequent adoption by ILAC, this has led to an increase in the number of PT/EQA providers being accredited around the world. This workshop, therefore, specifically addressed the experiences of implementing ISO/IEC 17043 both from the views of the PT/EQA providers and the accreditation bodies. In addition to addressing the implementation of ISO/IEC 17043, this workshop focused on further developments in performance assessment in microbiology and qualitative schemes, the status and needs of PT/EQA in developing areas of the world and advancements in preand postanalytical PT/EQA. These important topics addressed at this workshop were explored and discussed through a series of lectures and working group discussions. The diverse range of international delegates attending from different sectors provided a beneficial environment for the cross-fertilization of ideas. The workshop was enriched further with 52 poster contributions covering a wide range of topics and experiences concerned with PT/EQA. In conjunction with the workshop, training sessions on ‘‘Establishing Traceability and Uncertainty of Assigned Values’’ and ‘‘Assisting Participants to Assess/Estimate Their Measurement Uncertainty Using PT Results’’ were provided. This latest workshop once again proved a great success thanks to the hard work of the local organizers, the quality of the presentations and posters and just as importantly the active participation of all the delegates leading to lively debate and fruitful discussions. We are pleased to provide the papers on many of the presentations, posters and working group discussions in this Topical Focus on PT/ EQA issue of the Journal. B. Brookman (&) LGC Standards Proficiency Testing, Bury, UK e-mail: Brian.Brookman@lgcpt.com

Harmonization of Anti-Doping Rules in A Global Context (World Anti-Doping Agency-Laboratory Accreditation Perspective)

This article provides a review of the leading role of the World Anti-Doping Agency (WADA) in the context of the global fight against doping in sport and the harmonization of anti-doping rules worldwide through the implementation of the World Anti-Doping Program. Particular emphasis is given to the WADA-laboratory accreditation program, which is coordinated by the Science Department of WADA in conjunction with the Laboratory Expert Group, and the cooperation with the international accreditation community through International Laboratory Accreditation Cooperation and other organizations, all of which contribute to constant improvement of laboratory performance in the global fight against doping in sport. A perspective is provided of the means to refine the existing anti-doping rules and programs to ensure continuous improvement in order to face growing sophisticated challenges. A viewpoint on WADA's desire to embrace cooperation with other international organizations whose knowledge can contribute to the fight against doping in sport is acknowledged.

Can we trust automatic sphygmomanometer validations?

Hypertension is a leading risk factor for mortality. Detecting, treating and monitoring hypertensive patients require accurate blood pressure measurements. Protocols for validation of automatic sphygmomanometers exist, but quality control of validations is limited to peer review of published reports, which has severe limitations. An extensive international measurement framework provides quality assurance, traceability and laboratory accreditation for many measurements that are important to society, including industrial, scientific and trade measurements, medical imaging and medical laboratory testing. An important part of this quality assurance is external accreditation of laboratories that perform testing and calibration to the international standard ISO 17025 General requirements for the competence of testing and calibration laboratories. Automatic sphygmomanometer validation is a form of calibration and deserves quality control at least as good as other tests and calibrations that are important to society. It is suggested that laboratories that perform automatic sphygmomanometer validations should participate in the international measurement framework and be externally accredited by accrediting agencies that are members of the International Laboratory Accreditation Cooperation.

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.

How IAF and ILAC manage the recognition of Regional Accreditation Groups: the peer evaluation system of IAF and ILAC for Regional Accreditation Groups

The peer evaluation of single accreditation bodies in order to sign an Arrangement for Recognition of the international accreditation organizations International Accreditation Forum, Inc. (IAF) and International Laboratory Accreditation Cooperation (ILAC), whether performed by Regional Accreditation Groups or directly by IAF and/or ILAC, is standard practice. The fundamental requirements for such evaluations are well specified in documents. However, the careful evaluation of all their Arrangement members poses an enormous logistic task for IAF and ILAC, and the signatories can be evaluated more thoroughly within their Regional Groups. Hence, IAF and ILAC typically evaluate only the Regional Accreditation Groups and accept all signatories of a Regional Accreditation Group once successfully evaluated by their respective Regional Group. However, the requirements for the evaluation of a Regional Group are extensive, and the evaluation procedure is highly complicated and must be conducted very carefully in order to assure that the results of accreditation can be trusted. This article describes the evaluation procedure used by IAF and/or ILAC for Regional Groups wishing to sign the IAF/ILAC Arrangement. We wish to inform and to aid these Regional Groups setting out for evaluation, and also to build confidence in the IAF/ILAC Arrangements.

Some remarks on definitions and, in particular, on the definition of the term calibration

Confucius (Analects xiii:3) ‘It is not possible to have any valid argument until rigorously defined terms are agreed’. In radiation protection dosimetry, we perhaps need to take as the fundamental sources of our definitions for personal dosimetry and area monitoring, mainly those three committees—the Joint Committee for Guides in Metrology (JCGM), which gives definitions for metrology generally; the International Commission on Radiation Units and Measurements (ICRU), which gives basic physical quantities and units for ionising radiation; and the International Commission on Radiological Protection (ICRP) for quantities considering the health effect of ionising radiation, for example effective dose, equivalent dose and the quality factor/linear energy transfer function. The JCGM, chaired by the Director of the BIPM, is formed by the seven international organisations that had prepared the original versions of the Guide to the Expression of Uncertainty in Measurement (GUM) and the International Vocabulary of Basic and General Terms in Metrology (VIM), namely the International Bureau of Weights and Measures (BIPM), the International Electrotechnical Commission (IEC), the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC), the International Organization for Standardization (ISO), the International Union of Pure and Applied Chemistry (IUPAC), the International Union of Pure and Applied Physics (IUPAP) and the International Organization of Legal Metrology (OIML). In 2005, the International Laboratory Accreditation Cooperation (ILAC) joined the seven founder international organisations. The Joint Committee took on the work of the ISO Technical Advisory Group 4 (TAG 4), which had developed the GUM and the VIM. Two of the organisations involved in the JCGM, ISO and IEC are also jointly revising the ISO 31 series of standards as the new 80 000 series on quantities and units.

Residue analysis of tetracyclines in poultry muscle: Shortcomings revealed by a proficiency test

A proficiency test for tetracycline drug residues in poultry muscle was organized according to the guidelines of International Laboratory Accreditation Cooperation (ILAC) ILAC-G13:2000 (2000). For the proficiency test, three test materials were prepared. The homogeneity and stability of the materials during the study were demonstrated. Sixteen laboratories accepted the invitation to participate in the proficiency test; 11 laboratories reported results within the time frame of the study. Most notably, only four of the participating laboratories complied with the definition of the maximum residue limit (MRL) concerning the inclusion of 4-epimers as stated in European Commission Regulation 281/96 (1996). Most participants reported values for the decision limit (CCα) and detection capability (CCß) and hence were already in compliance with European Commission 2002/657/EC (2002) for this aspect of method validation. However, some CCα and CCß values were not in agreement with the actual within-laboratory reproducibility calculated from the results reported in this proficiency test. Although most laboratories obtained satisfactory results, it is clear that an effort is needed to include 4-epiOTC, 4-epiTC and 4-epiCTC in the analytical methods. Moreover, reconsideration of values determined for CCα and CCß with respect to their accuracy may be necessary in some cases.