Performance of the RACE Prehospital Triage Score During Working and Nonworking Hours.

Background: Prehospital triage scores aim to identify large vessel occlusions (LVOs) in the field; however, their real-world performance and accuracy across a 24-hour period remains unknown. In this study, we compare the positive predictive value of the prehospital Rapid Arterial occlusion Evaluation (RACE) score for the detection of LVO during working hours and nonworking hours. Methods: We performed a retrospective review of all patients presenting with a RACE score of ≥5 at one comprehensive and one thrombectomy-capable hospital between July 2015 and December 2019. Patients were dichotomized to those presenting during "working hours" (7:00 am to 6:00 pm on weekdays) or "nonworking hours" (6:01 pm to 6:59 am on weekdays or anytime during weekends). The primary outcome was diagnosis of LVO. Secondary outcomes included diagnosis of acute neurovascular syndromes, door-to-treatment time metrics, and a modified Rankin Scale of ≤2 in those undergoing mechanical thrombectomy. Results: Of the 701 patients with RACE score ≥5, 687 patients were included (355 nonworking hours and 332 working-hours cohorts). Mean age was 71 and 72 years in the nonworking hours and working hours groups, respectively ( Conclusions: The RACE score shows a consistent positive predictive value in determining LVO during working and nonworking hours. However, it is more accurate in determining acute neurovascular syndromes during nonworking hours, which is driven by a decrease in stroke mimics during this time.