Reliability of the National Triage Scale with changes in emergency department activity level

Abstract

Abstract Aim To assess the reliability of the National Triage Scale (NTS) by determining whether the activity level of an emergency department influences triage category assignment. Setting Emergency Department, The St George Hospital, a Sydney metropolitan teaching hospital emergency department. Methods A prospective study of all patients presenting over a six‐month period. Triage category (TC) assignment distribution and admission rate in each TC was determined for three levels of departmental activity (Quiet, Normal, Busy) defined by the number of presentations to the department in the previous two hours. Results Of 17,561 presentations examined, the proportion of patients assigned to each TC did not significantly differ for NTS1,2,3 or 4. The percentage of patients assigned to NTS5 for Quiet periods was 9.0% (95%CI 7.9–10.0%), Normal 7.0% (6.5–7.6%) and Busy 6.6% (6.0–7.2%) (p<0.001). The admission rate for NTS4 for all levels of activity was 36% (35–37%) and exceeded the NTS guideline of 20–30%. Busy 16% (13–20%) and Normal 16% (13–19%) NTS5 patients had a slightly higher admission rate than Quiet NTS5 patients 10% (6–14%) (p=0.049) and exceeded the NTS guideline of 5–10%. Admission rates for NTS1,2 and 3 were within NTS guidelines for all activity levels. Conclusion The NTS can be applied consistently, independent of the emergency department activity level. Admission rate analysis indicates that the slightly higher proportion of NTS5 patients presenting during Quiet periods were of genuine low acuity. NTS guideline comparison suggests either 10% of NTS4 and 5% of NTS5 patients at this hospital should have been triaged to a higher TC or that the NTS admission rate guidelines may need revision.