Table 1

Evidence summary of the most commonly used triage systems 

Canadian Triage And Acuity ScaleEmergency Severity IndexManchester Triage System
Triage system characteristics
DescriptionList, based on presenting signs and symptomsFlowchart, based on physical signs and expected resource useMultiple flowcharts, based on presentational signs and symptoms
No of levels555
Classification and waiting timeLevel I, Immediate
Level II, 15 min
Level III, 30 min
Level IV, 60 min
Level V, 2 hours
Emergent, 14 min
Urgent, 60 min
Semiurgent, 2 hours
Non-urgent, 24 hours
Very urgent, 10 min
Urgent, 60 min
Standard, 2 hours
Non-urgent, 4 hours
Quantity of evidence
Total no of evaluations132115
Evaluations in children947
Evaluations in elderly120
Diversity of evidence (range)
No of hospitals per study1–121–71–4
Inclusions per study481–550 940180–37 974872–31 622
Hospital census10 000–75 00010 000–90 0007000–190 000
Hospitalisation rate8%–47%10%–62%5%–33%
Risk of bias
High risk of bias in at least one domain54%81%67%
High risk of bias in >1 domain15%23%13%