Introduction Traumatic brain injury (TBI) is a leading cause of death and disability in young adults. Reorganisation of trauma services with direct triage of suspected head injury patients to trauma centres may improve outcomes following TBI. This study aimed to determine the sensitivity of principal English triage tools for identifying significant TBI.

Methods We performed a diagnostic cohort study using data prospectively collated from the Trauma Audit and Research Network database between 2005 and 2011. Adult head injury patients were retrospectively classified according to London Ambulance Service (LAS) and Head Injury Transportation Straight to Neurosurgery study (HITS-NS) triage criteria. Sensitivity and specificity were then calculated against a reference standard of significant TBI, comprising head region abbreviated injury score (AIS) ≥3 or neurosurgical operation.

Results 6559 patients were included in complete case analyses. The LAS and HITS-NS triage tools demonstrated sensitivities of 44.5% (95% CI 43.2 to 45.9) and 32.6% (95% CI 31.4 to 33.9), respectively, for identifying significant TBI patients. False negative significant TBI cases were relatively older, more likely to be female, more frequently secondary to low-level falls, and were less likely to have very severe AIS five or six head injuries, p<0.01.

Conclusions A considerable proportion of significant head injury patients may not be triaged directly to trauma centres. Investment is therefore necessary to improve the accuracy of existing triage rules and maintain expertise in TBI diagnosis and management in non-specialist emergency departments.