Diagnostic accuracy of emergency department triage systems for predicting clinical severity: A systematic review and meta-analysis of five-level triage scales.

Five-level systems such as the Emergency Severity Index (Emergency Severity Index), Manchester Triage System (Manchester Triage System), Canadian Triage and Acuity Scale (Canadian Triage and Acuity Scale), Australasian Triage Scale (Australasian Triage Scale), and South African Triage Scale (South African Triage Scale) are widely used, but their reported performance varies across settings and outcome definitions.

This systematic review and meta-analysis evaluated the predictive validity of these triage systems for prespecified surrogate outcomes, including ICU admission, critical intervention, hospital admission, and short-term mortality, rather than assuming that any single endpoint represented a definitive gold standard for true emergency severity.