GERIATRICS/ORIGINAL RESEARCH Triage of Geriatric Patients in the Emergency Department: Validity and Survival With the Emergency Severity Index Michael R. Baumann, MD Tania D. Strout, RN, BSN From the Department of Emergency Medicine, Maine Medical Center, Portland, ME. Study objective: We evaluate the validity of the Emergency Severity Index (version 3) (ESI) triage algorithm in a geriatric emergency department (ED) population and determine the association between ESI categorization and survival. Methods: Validity was assessed using a retrospective analysis of hospitalization, ED length of stay, and observed resource use compared with resource utilization estimated at triage by the ESI. Survival analysis was conducted for the same cohort. The study was exempted by the hospital institutional review board, and the requirement for informed consent was waived. Results: During the investigation, 1,087 patients older than 65 years were registered in the ED. Six patients were identified as direct admissions, and 152 were found to be repeat visitors, leaving 929 subject visits for analysis. In this cohort, hospitalization was associated with ESI triage assignment (Kendall’s -b=-0.476; 95% confidence interval [CI] -0.524 to -0.425). The area under the receiver operating characteristic curve for the predictive ability of the ESI for hospitalization was 0.77 (95% CI 0.748 to 0.806). Length of stay was associated with ESI assignment (Kruskal-Wallis test, P=.000). The relationship between triage categorization and resource utilization was significant (Spearman’s correlation=-0.683; 95% CI -0.716 to -0.647). ESI categorization was associated with vital status at 1 year (Kaplan-Meier  2 67.85; df=4; P=.0000). Conclusion: When used to triage patients older than 65 years, the ESI algorithm demonstrates validity. Hospitalization, length of stay, resource utilization, and survival were all associated with ESI categorization in this cohort. [Ann Emerg Med. 2007;49:234-240.] 0196-0644/$-see front matter Copyright © 2007 by the American College of Emergency Physicians. doi:10.1016/j.annemergmed.2006.04.011 INTRODUCTION Background The Emergency Severity Index (ESI) version 3 algorithm is a 5-level triage instrument that has been shown to demonstrate reliability and validity in a wide range of patient populations. 1-7 The algorithm was designed to evaluate both patient acuity and anticipated resource utilization necessary to reach disposition. 3 The ESI instrument stratifies emergency department (ED) patients into 5 mutually exclusive categories, with ESI category 1 assignment representing the most acute, high-resource- utilization patients (cardiac arrest) and ESI category 5 representing patients who are the least acute and resource intense (medication refill). 7 EDs nationally have identified crowding as one of their top areas of concern. The number of ED visits continues to climb, with fewer departments available to handle the volume. 8 Coupled with hospital inpatient capacity that has become more constrained, entire initiatives have developed focusing on crowding and its ED impact. 9 A reliable and valid triage instrument to accurately characterize waiting patients becomes essential for patient safety when one considers the resultant increased length of stay of ED patients. IMPORTANCE Despite the increasing size of the older population and evidence suggesting that elders more frequently utilize emergency services than their younger counterparts, little is known about the validity of many frequently used instruments in the geriatric population. 10 Several instruments have been tested in the geriatric population to risk-stratify after an ED visit. The Triage Risk Screening Tool is an instrument that stratifies older ED patients who are discharged from the ED into risk groups for ED revisit, hospitalization, and nursing home placement within the next 30 days and 120 days. 11 The Identification of Seniors At Risk screening tool has been used in a discharged geriatric ED population to detect severe functional impairment, increased depressive symptoms, and high 234 Annals of Emergency Medicine Volume , .  : February 