Experience of the implementation of EA-4/18

Abstract

The standard ISO/IEC 17025 (sub-clause 5.9) requires that the validity of tests results is monitored by laboratories and one of the tools that can be used is the participation in proficiency testing (PT). To give guidance to accreditation bodies (ABs) on how to evaluate the level and frequency of participation in PT and to assist laboratories in determining their own levels and frequency of participation, a guidance document, EA-4/18 (Guidance on the level and frequency of proficiency testing participation), was established in 2010 by the European Cooperation for Accreditation (EA). There has been various feedback from the analytical community in Europe suggesting that some laboratories have experienced mixed messages from different assessors as to the level and frequency of PT participation required and that there may be a lack of harmonization between accreditation bodies. Given the concerns raised, the EEE-PT (EA-Eurachem-Eurolab) WG undertook a survey, with the support of the EA Laboratory committee, to ascertain the experience from the EA accreditation bodies with implementing the guidance. The survey was sent to the EA full and associate members. The outcome of the survey showed that EA-4/18 is implemented in a harmonized way throughout the accreditation bodies, but the concept included in EA-4/18 can be difficult to understand. As there are no specific indications in EA-4/18, on the level and frequency of participation, the implementation by each laboratory of the concept found in EA-4/18 can vary, even if the laboratories are active in the same field. In the same way, different assessors can have different views on the strategy established by the laboratory, therefore leading to the impression that the laboratories are treated differently. A majority of ABs wish to revise EA-4/18 as it is considered as a helpful guidance, but more clarification of the concept and additional examples should be included in the revised version, if EA decides to do so.