The Emergency Severity Index Triage Algorithm Version 2 Is Reliable and Valid

Objectives: Initial studies have shown improved reliability and validity of a new triage tool, the Emergency Severity Index (ESI), over conventional three-level scales at two university medical centers. After pilot implementation and validation, the ESI was revised to include pediatric and updated vital signs criteria. The goal of this study was to assess ESI version (v.) 2 reliability and validity at seven emergency departments (EDs) in three states. Methods: In part 1, interrater reliability was assessed using weighted kappa analysis of written training cases and postimplementation by a random sampling of actual patient triages. In part 2, validity was analyzed using a prospective cohort with stratified random sampling at each site. The ESI was compared with outcomes including resource consumption, inpatient admission, ED length of stay, and 60-day all-cause mortality. Results: Weighted kappa analysis of interrater reliability ranged from 0.70 to 0.80 for the written scenarios (n= 3,289) and 0.69 to 0.87 for patient triages (n= 386). Outcomes for the validity cohort (n= 1,042) included hospitalization rates by ESI triage level: level 1, 83%; 2, 67%; 3, 42%; 4, 8%; level 5, 4%. Sixty-day all-cause mortality by triage level was as follows: level 1, 25%; 2, 4%; 3, 2%; 4, 1%; and 5, 0%. Conclusions: ESI v. 2 triage produced reliable, valid stratification of patients across seven sites. ESI triage should be evaluated as an ED casemix identification system for uniform data collection in the United States and compared with other major ED triage methods.