Study objectives: Triage is an initial assessment of acuity and sorting process applied to patients on presentation to an emergency department (ED). It is believed that patients triaged as having a higher level of acuity require a greater number of ED resources during their ED visit. This study seeks to prospectively measure and compare the ability of the 2 most commonly used, 5-level triage tools in North America, the Emergency Severity Index and the Canadian Triage and Acuity Scale, to predict the ED resources utilized by each patient during his or her visit.

Methods: In this multicenter, prospective, observational cohort study of a population-based random sample of patients triaged at 2 EDs during a 4-month period, all patients presenting to the ED within the study periods were simultaneously and independently triaged by 2 nurses each using 1 of the 2 triage tools and blind to each other's assessment. The patients were followed up during their stay in the ED by a third research nurse blind to the triage assessments who recorded the resources utilized for that patient using a standardized data collection form until disposition.

Results: Correlational analyses of the 486 cases revealed no significant difference between the ability of the Emergency Severity Index (r=0.524) and the Canadian Triage and Acuity Scale (r=0.485) to predict resource utilization.

Conclusion: Triage scales, although valid and reliable measures of acuity, are only moderately accurate measures of ED resource utilization.