A new definition of major trauma that combines injury severity with urgent trauma-team interventions identified more high-risk patients and deaths than injury scoring alone.

• In 2.68 million National Trauma Data Bank patients, 22.4% met the combined definition, versus 17.8% with Injury Severity Score above 15.
• The combined definition had the best discrimination for 24-hour mortality (area under the curve, 0.83), compared with 0.78 for injury score alone and 0.79 for interventions alone.
• It identified 26% more 24-hour deaths and 29% more in-hospital deaths than either existing approach alone.

Surgeons and trauma systems may improve triage and benchmarking by incorporating what the trauma team must do—not just the injuries documented.