The quality assurance of proficiency testing programs for animal disease diagnostic laboratories.

Laboratory data credibility has 3 major components: 1) valid methods, 2) proficiency testing (PT) to verify that the analyst can conduct the method and to compare results of other laboratories using the same method, and 3) third-party accreditation to verify that the laboratory is competent to conduct testing and that the method validation has been done within the environment and requirements of an effective quality-management system. Participation in external PT programs by a laboratory is strongly recommended in International Organization for Standardization/International Electrotechnical Commission International Standard 17025. Most laboratory accreditation bodies using this standard require that laboratories participate in such programs to be accredited. Internal PT is also recommended for each analyst. Benchmarking, or comparison between laboratories using PT or reference materials, is also recommended as part of the validation and evaluation of test methods. These requirements emphasize the need for proficiency test providers to demonstrate their competence. Requirements for competence are documented in national and international standards and guidelines, and accreditation is available for providers. This article discusses the activities and the components that are necessary and recommended for PT projects and programs for animal disease diagnostic testing. These are based on the requirements of the national and international standards, which address this subject, and on the experience of the author. The accreditation of external PT programs is also discussed. Organizations that accredit PT providers or that provide PT programs are listed. Existing references, guidelines, and standards that are relevant to PT in veterinary diagnostic laboratories are discussed.