Left Without Being Seen: A Scoping Review of a Silent Crisis in Emergency Departments.

Background: Left Without Being Seen (LWBS) rates are widely recognized as a key quality indicator in Emergency Departments (ED) worldwide. Their clinical relevance is substantial, given the documented association between LWBS and increased morbidity and mortality among patients presenting to the ED. However, the available evidence is extensive and highly heterogeneous; therefore, a scoping review represents a more appropriate approach for synthesizing the evidence than a systematic review or meta-analysis. Objective: This scoping review aims to synthesize current evidence regarding population characteristics, underlying determinants, and potential interventions associated with LWBS rates, pondering the need to strengthen strategies for identifying and reducing these events. Design: Scoping review conducted according to PRISMA-ScR guidelines. We searched four databases (PubMed, Scopus, Oxford Academic, and EBSCO) between Jan 01, 2020 - Dec 31,2025. To meet the eligibility criteria, studies were required to be observational analytical, interventional, or evidence synthesis, given the limited evidence found, posters involving studies of human participants in ED settings. Results: Ninety-four publications were included with de eligibility criteria Most studies were interventional and conducted in North America; however, systematic reviews and additional studies from Europe, Asia, Australia, South America, and the Middle East were also identified. Reported LWBS rates varied widely across settings and were influenced by both community-level and individual-level factors, including demographic characteristics, EDs staffing, time of presentation, chief complaint, and facility resources, as well as contextual factors such as the COVID-19 pandemic. The available evidence demonstrated considerable heterogeneity in the definition and characterization of LWBS causes, largely due to differences in reporting practices, documentation, and descriptions of events related to this outcome. Numerous interventions aimed at reducing LWBS rates were described. Conclusion: LWBS is a key emergency care quality indicator driven by waiting times, crowding, and temporal factors. It predominantly affects low-acuity, socioeconomically vulnerable adults. Physician-in-triage reduces LWBS, while predictive models identify high-risk patients. Associated with revisits and mortality, LWBS requires flow optimization and context-adapted strategies. Standardized frameworks are needed to strengthen evidence.