STUDY OBJECTIVE: Field triage guidelines recommend that emergency medical services (EMS) providers consider transport of head-injured older adults with anticoagulation use to trauma centers. However, the triage patterns and the incidence of intracranial hemorrhage or neurosurgery in these patients are unknown. Our objective is to describe the characteristics and outcomes of older adults with head trauma who are transported by EMS, particularly for patients who do not meet physiologic, anatomic, or mechanism-of-injury (steps 1 to 3) field triage criteria but are receiving anticoagulant or antiplatelet medications. METHODS: This was a retrospective study at 5 EMS agencies and 11 hospitals (4 trauma centers, 7 nontrauma centers). Patients aged 55 years or older with head trauma who were transported by EMS were included. The primary outcome was the presence of intracranial hemorrhage. The secondary outcome was a composite measure of inhospital death or neurosurgery. RESULTS: Of the 2,110 patients included, 131 (6%) had intracranial hemorrhage and 41 (2%) had inhospital death or neurosurgery. There were 162 patients (8%) with steps 1 to 3 criteria. Of the remaining 1,948 patients without steps 1 to 3 criteria, 566 (29%) had anticoagulant or antiplatelet use. Of these patients, 52 (9%) had traumatic intracranial hemorrhage and 15 (3%) died or had neurosurgery. The sensitivity (adjusted for clustering by EMS agency) of steps 1 to 3 criteria was 19.8% (26/131; 95% confidence interval [CI] 5.5% to 51.2%) for identifying traumatic intracranial hemorrhage and 34.1% (14/41; 95% CI 9.9% to 70.1%) for death or neurosurgery. The additional criterion of anticoagulant or antiplatelet use improved the sensitivity for intracranial hemorrhage (78/131; 59.5%; 95% CI 42.9% to 74.2%) and death or neurosurgery (29/41; 70.7%; 95% CI 61.0% to 78.9%). CONCLUSION: Relatively few patients met steps 1 to 3 triage criteria. For individuals who did not have steps 1 to 3 criteria, nearly 30% had anticoagulant or antiplatelet use. A relatively high proportion of these patients had intracranial hemorrhage, but a much smaller proportion died or had neurosurgery during hospitalization. Use of steps 1 to 3 triage criteria alone is not sufficient in identifying intracranial hemorrhage and death or neurosurgery in this patient population. The additional criterion of anticoagulant or antiplatelet use improves the sensitivity of the instrument, with only a modest decrease in specificity.