Introduction: A formalized trauma response team is designed to optimize the quality and progress of patient care for severely injured patients in order to reduce mortality and morbidity. The goal of this study was to determine over- and undertriage and to evaluate if a physicianmanned pre-hospital response (MD-EMS) would reduce overtriage. Overtriage was defined as the process of overestimating the level of injury sustained by an individual. Material and methods: This was a retrospective study. All patients admitted with trauma team activation (TTA) (n = 1,468) during a four-year period (2007-2011) were included. Undertriage was estimated by assessing the fraction of major trauma patients (New Injury Severity Score (NISS) > 15) admitted to Viborg Regional Hospital in the project period without TTA. RESULTS : For each year, overtriage was 88.3% (2007), 89.9% (2008), 92.8% (2009) and 88.2% (2010); an NISS > 15 was seen in a total of 149 patients. Undertriage was 0.39% (2007), 0.46% (2008), 0.51% (2009) and 1.10% (2010); an NISS > 15 was seen in a total of 21 patients who were not received by a trauma team. We observed no significant difference in the NISS (p = 0.19) or in over-/undertriage (p = 0.76 and p = 0.058) when comparing the years before with the years after the introduction of the MD-EMS response. Conclusion: Our study shows a high degree of overtriage and a very low undertriage according to the currently accepted protocol guidelines. No effect was seen after the introduction of the MD-EMS. Funding: not relevant. Trial registration: In compliance with the Scientific Committees for the Region of Central Jutland, approval for our project was obtained prior to collecting data.undertriage according to the currently accepted protocol guidelines. No effect was seen after the introduction of the MD-EMS.