Table 1 Inclusion and exclusion criteria

Study population

Patients of all age ages in the need for acute care (acutely ill or seriously injured somatic or psychiatric patients)

Intervention

Patient prioritizing by the use of a validated triage system in the pre-hospital setting; face-to-face or telephone triage-assessment

Comparison

Acutely ill or seriously injured patients who were assessed with a triage system different from that of the intervention, or who were not triaged at all in the same type of setting

Outcomes

Health outcomes (mortality, morbidity)

Patient safety (for example undertriage)

Patient satisfaction

Job-satisfaction with the triage systems among health workers

Resources use (for example overtriage)

To what degree triage was completed (goal achievement)

The quality of the information exchange between the different settings of the EMS (for example the quality of documentation)

Study design

Systematic review of high quality (see checklist, Additional file 2)

Randomized controlled trial (RCT)

Non-randomized controlled study (non-RCT)

Controlled before-and-after study (CBA)

Interrupted time series analysis (ITS)

Exclusion

Studies were excluded if triage assessment was done in the hospital setting only without including triage assessment in any of the pre-hospital settings, if the patients were not acutely ill or seriously injured, or if there was no use of a comparison for the evaluation of the effects of a triage system or an ITS design