Table I.

Criteria for inclusion of abstracts.

Theme	Definition	Inclusion	Exclusion
Setting/population:
Out-of-hours care	Care (partly) after office hours	At least partly out-of-hours care	Only during office hours
Primary care	Care for patients with a first presentation of a medical complaint	Primary care centres, paediatrics, ambulance care, and emergency departments	Disease specific telephone lines, secondary medical care
Telephone triage	Telephone contact in which the caregiver asked questions to estimate urgency and necessary care level, in order to give advice or refer the patient	Computerised decision support systems, triage professionals, telephone triage advice, and referral services	Advice only services, computerised triage systems or websites (without a triage professional)
Outcome:
Safe performance	Triage resulting in an appropriate outcome (i.e. no under-triage, under-estimation, or under-referral)	Appropriateness, adequacy, under-triage	Appropriateness only related to efficiency
Adverse events	Triage resulting in potential harm due to inappropriate performance and/or delay	Errors/mistakes, near accidents, harm, mortality, unplanned attendance at ED, unplanned admissions within 24 hours
Other criteria:
Study design	All levels of evidence were accepted	Empirical quantitative studies, that is controlled and observational studies in clinical practice	Descriptive studies, editorials, reviews, interviews, letters, or comments
Other			Non-English, no abstract, no full text article available