The Role of Triage in Italian Emergency Departments: A Systematic Review on Emergency Code Distribution, Over-Triage and Diagnostic Overuse

Abstract

Triage is a core function of Emergency Departments (EDs), designed to ensure that patients are rapidly assessed and prioritized according to clinical urgency rather than order of arrival. In Italy, ED triage has undergone a major organizational transition from the traditional four-colour code system to a five-level model, aligned with international standards and intended to improve clinical safety, equity of access, patient flow and resource allocation. However, triage is not only a prioritization tool; it also influences downstream diagnostic pathways, waiting times, use of ED resources, and the risk of over-triage, under-triage, inappropriate access and diagnostic overuse. This systematic review examines the role of triage in Italian Emergency Departments, with particular focus on the distribution of emergency codes, the relationship between triage categories and patient complexity, and the phenomenon of overdiagnosis or diagnostic overuse in low-acuity patients. A structured review was conducted using national Italian triage guidelines and peer-reviewed scientific literature on ED triage, crowding, inappropriate access, over-triage, under-triage, diagnostic testing and patient flow. The evidence indicates that the transition to a five-level triage system improves discrimination between levels of urgency and may reduce under-triage, although a modest increase in over-triage may occur. Low-acuity patients, often classified as green, white or equivalent low-priority categories, represent a relevant proportion of ED demand and may contribute to overcrowding, diagnostic escalation and inefficient use of resources. Nevertheless, overdiagnosis in EDs is not merely the result of patient misuse, but arises from the interaction between defensive medicine, limited access to primary care, patient expectations, medico-legal pressure, availability of diagnostic technologies and organizational constraints. Triage should therefore be interpreted as a clinical governance tool that must be integrated with evidence-based protocols, continuous staff training, audit systems, territorial healthcare pathways and diagnostic stewardship strategies.