Measuring what matters: Redefining undertriage using trauma team actions

INTRODUCTION: Evaluating triage efficiency, particularly undertriage (UT), is an important quality improvement activity for trauma centers and supports selection of optimal trauma activation criteria. This study aimed to compare two existing methods (Cribari Matrix Method [CMM] and the Standardized Triage Assessment Tool [STAT]) to a novel method using eight High-Intensity Time-Sensitive (HITS) interventions adapted from Trauma Quality Improvement Program process-of-care measures. METHODS: This multicenter, retrospective study identified trauma patients admitted from 2017 to 2019 using trauma registry data including trauma activation status: full trauma activation (fTA+) or nonfull trauma activation (fTA-). Undertriage rate was assessed using CMM (Injury Severity Score >15 and fTA-), STAT (CMM UT and Need for Trauma Interventions +), and HITS interventions (HITS+ and fTA-); UT denominator was all fTA- patients. Among fTA- patients, UT patients were compared with appropriately triaged patients on total mortality (in-hospital death plus hospice) using multivariable generalized linear mixed models. RESULTS: Thirty-seven Level I/II trauma centers enrolled 158,696 patients (88.0% blunt, 21.7% fTA+, median age of 55 years, median Injury Severity Score of 9, 4.4% total mortality). Undertriage rate was lowest using the HITS interventions method (3.8%) versus STAT (5.1%) and CMM (11.1%) (both p < 0.001). Compared with CMM or STAT, the HITS interventions method showed significantly higher adjusted odds ratio for total mortality in UT versus appropriately triaged: adjusted odds ratio (95% confidence interval) of CMM, 6.67 (6.13-7.26); STAT, 12.55 (11.40-13.82), and HITS, 15.04 (13.48-16.78). CONCLUSION: Compared with CMM and STAT, HITS interventions method not only reduced the number of patients categorized as UT but also isolated those at the highest risk of mortality. Thus, HITS interventions method provides a streamlined, data-driven means to calculate UT rates using registry data and guides performance improvement reviews to patients who were not fTA but might have benefited from full trauma team intervention.(J Trauma Acute Care Surg . 2026;100:906-914. © 2026 American Association for the Surgery of Trauma.). LEVEL OF EVIDENCE: Therapeutic/Care Management; Level III.