Quality assurance, accreditation, and certification: needs and possibilities.

Demonstrable quality of laboratory services entails two parts. First, one needs a quality policy statement, identification of user needs, choice of measurement procedures, reference measurement system to provide traceability, control materials, and proficiency testing with materials having reference-measurement-assigned values. Second, it may be useful to obtain recognition of competence in addition to the director's certificate, such as Good Laboratory Practice (when studying toxicity of chemicals), ISO 9000 certification of a self-defined quality system, nongovernmental professional accreditation, or, most demanding, governmental accreditation according to European Standard EN 45,001 with some modifications. These require external quality audit; ISO and EN also require a quality manual, which is valuable documentation in any case.