This app is only available in Dutch (Nederlands) or French (Français). This app is based on an algorithm that provides an overview of recommended routine tests for adults prior to planned surgery, with the exception of transplants and heart and lung operations; this algorithm has been developed as part of the KCE report 280 (2017). It is intended for clinicians involved in preoperative preparation and the operation itself. It may also be useful to patients and their families. The algorithm is available in PDF format at https://preop.kce.be/en/ If you have any questions or problems with the app, please use the contact link on the website https://preop.kce.be/en/