Decision-making is the major component in triaging emergency department patients. Influencing factors on decision-making have been identified but it`s not clear how much of the decision is based upon scientific criteria. The objective of this study was to determine frequency of using reliable and valid guidelines by nurses in emergency departments.

It was a descriptive survey study. The questionnaire was composed of demographic data, evidence-based triage questions (15) and triage decision-making questions (10). The questionnaire reliability was 0.87 using the test-retest method. Content validity was considered based upon Canadian Triage and Acuity Scale.

70 nurses from 10 emergency departments participated. 40 % of nurses` responses to evidence-based questions was correct. The percentage of inter-rater agreement between nurses was moderate (0.56) related to decision-making questions. No valid and reliable guideline was utilized in emergency departments.

Nurses` decision-making was poorly based on evidence-based criteria. Low level of nurses` knowledge about triage may be derived from lack of official and specialized triage training courses. Academic triage courses establishment and development of national triage scale are recommended.