Triage is a process used in hospitals to sort and prioritize patients based on the severity of their injuries or illnesses. The term "triage" comes from the French word "trier," which means to sort or sift. The goal of triage is to provide effective and prioritized care to patients while optimizing resource usage and timing. Triage can be broken down into three phases: prehospital triage, triage at the scene of the event, and triage upon arrival to the emergency department.

When a patient arrives at the emergency department, a triage nurse performs a brief, focused assessment and assigns the patient a triage acuity level, also known as a "triage score". The acuity level is a proxy measure of how long the patient can safely wait for medical evaluation and treatment. Patients are then prioritized based on their triage score, with those in the most urgent need of care receiving treatment first.

Triage is an important process in ensuring that patients receive care in an appropriate and timely manner by emergency care providers. However, incorrectly triaged patients could sustain further injury and complications. The main limitations of todays triage systems lie in their lack of sensitivity and specificity. Triage nurses are skilled multi-taskers and excellent communicators who are able to make decisions quickly and confidently. They are indispensable members of the emergency department team who work to ensure all patients receive the best possible service.