ambulance clinicians havebeen required to make triage decisions relating to severity of injury, and appropriate destination for thepatient, which may require ‘bypassing’ the nearest Emergency Department. A ‘Trauma Unit Bypass Tool’is utilised in this process. The Major Trauma Triage tool smartphone application (App) is a digital representationof a tool, available for clinicians to use on their smartphone. Prior to disseminating the application,validity and performance against the existing paper-based tool was explored.