High-Accuracy Performance of a Simplified Binary Triage System in Military Trauma

Importance: Accurate prehospital triage is critical for prioritizing evacuation and allocating medical resources in combat settings characterized by diagnostic uncertainty and operational constraints. Simplified, judgment-based triage systems may improve feasibility and adherence but require validation under real-world conditions. Objective: To evaluate the performance of a simplified binary field triage system in identifying severely injured trauma casualties under real-world combat conditions. Design, Setting, and Participants: This cohort study was conducted between October 27, 2023, and January 19, 2025. The setting was a military prehospital medical system during a recent conflict. Included were military trauma casualties treated and evacuated by the Israel Defense Forces Medical Corps. Main Outcomes and Measures: Field triage designations (urgent vs nonurgent) were compared with anatomic injury severity defined by the Abbreviated Injury Scale (AIS) and Injury Severity Score (ISS), as well as the need for trauma intervention (NFTI). Primary outcomes included undertriage and overtriage rates. Results: Among 4522 casualties (median [IQR] age, 23 [20-29] years; 4479 male [99%]), a judgment-based binary approach was associated with an undertriage rate, classification as nonurgent despite severe injury, of 8.5% (95% CI, 6.81%-10.54%) among casualties with any injury with an AIS score of 3 or greater. Among casualties with major trauma (ISS ≥16), the undertriage rate was 3.6% (95% CI, 2.25%-5.67%). Corresponding sensitivities were 91.5% (95% CI, 89.46%-93.19%) and 96.4% (95% CI, 94.33%-97.75%), respectively. Overtriage, defined as urgent triage in the absence of severe injury, was 62.7% (95% CI, 60.65%-64.77%). Using the NFTI definition, undertriage was 8.8% (95% CI, 7.33%-10.62%), and overtriage was 50.2% (95% CI, 48.06%-52.32%). In undertriaged patients with major trauma, severe head and thoracic injuries were most common. Conclusions and Relevance: In this cohort study, a simplified, judgment-based binary field triage system demonstrated high sensitivity with low undertriage for major trauma in combat settings, at the cost of substantial overtriage. These findings support the use of simple triage approaches under operational constraints while highlighting the need to improve detection of less apparent injuries without compromising simplicity.