In order to support the harmonised interpretation and the implementation of the Commission Implementing Regulation 2021/808 laying down requirements for the performance of methods for the analysis of veterinary drug residues, COM has asked the EURLs to provide guidance documents dealing with specific aspects which might require supplemental information. Now, the EURL guidance document on method extension has been finalised and is available as of today.

The document provides some general reflections on the extension of analytical methods to additional analytes, matrices or the adaption of the validated concentration range. Furthermore, model approaches and practical examples for the extension of methods previously validated applying the conventional and the alternative validation approach are introduced.

The drafts of the guidance document were presented and discussed during the meetings of the Working Group on Residues of Veterinary Medicinal Products in Food of Animal Origin and during the EURL workshops. Additionally, all NRLs had the opportunity to provide comments and suggestions in order to increase the document’s practicality. Although the guidance document represents the EURLs’ interpretation of CIR (EU) 2021/808 and is meant as a support for all laboratories, it is not seen as mandatory to follow. Other approaches are possible, if they provide plausible and comparable results.