Proficiency testing exercises provide an independent assessment of laboratory data compared either with reference values or with the performance of a similar laboratory. Thus, they provide the organisation with information about any technical aspects or alert about the need for further investigation on any potential issues within the laboratory.

Participation in these exercises also enables to check either the performance in new tests or measurements in those that are carried out infrequently. Also, it allows to compare the results obtained using different methods (or different concentration levels), helping select the methodology that best suits its features and the clients’ needs. 

In this sense, only accredited proficiency testing providers are able to offer this guarantee, as they are the only ones having the necessary technical competence in compliance with the requirements of UNE-EN ISO/IEC 17043.