The current document is anupdate of the guidelines developed by the EUCAST subcommittee on detection of resistance mechanisms. The EUCAST Steering Committee has carried out the current update. The document has been developed mainly for routine use in clinical laboratories and doesnot cover technical procedures for identification of resistance mechanisms at a molecular level by reference or expert laboratories. However, much of the content is also applicable tonational reference laboratories. Furthermore, it is important to note that the document does not cover screening for asymptomatic carriage (colonization) of multidrug-resistant microorganismsor direct detectionof resistancein clinical samples.