Triage is a systematic method of prioritization used in medical settings to determine the order in which patients receive care. This process is rooted in the objective of maximizing positive outcomes for the largest number of people, especially when resources like time, staff, and medical supplies are limited. By quickly assessing and categorizing all individuals, healthcare providers can allocate their efforts most effectively. Triage ensures that those with the most urgent conditions receive immediate attention, while those who can safely wait are monitored until a provider is available.
Where Triage Happens
The concept of sorting the wounded first developed within military field medicine, notably during the Napoleonic Wars, where French surgeons established a system to treat soldiers based on their injuries rather than their rank. This historical need to make immediate, life-and-death decisions under conditions of extreme scarcity established the foundation for modern civilian triage.
The most common setting for triage is the hospital Emergency Department (ED), where it manages the flow of patients arriving with various complaints. Triage is also applied during mass casualty incidents (MCI), such as natural disasters, large-scale accidents, or terrorist events. In these high-stress situations, the local healthcare infrastructure is quickly overwhelmed, forcing responders to focus on saving the greatest number of lives possible with finite resources.
The Triage Process and Priority Levels
Triage involves a rapid, standardized assessment that assigns each patient a priority level based on their medical stability and potential for deterioration. In the United States, the Emergency Severity Index (ESI) is the most widely adopted five-level triage scale used in hospital emergency departments. ESI uses a numerical system from Level 1, requiring immediate intervention, to Level 5, which represents a non-urgent condition.
The initial assessment focuses on whether the patient requires immediate life-saving intervention, which automatically places them at ESI Level 1. If not, the nurse next determines if the patient is in a high-risk situation or experiencing severe pain, which typically assigns them an ESI Level 2. For patients who are relatively stable, the next step in the algorithm is to estimate the number of resources, such as lab tests, imaging, or specific medications, that will be required for their care.
A patient expected to need multiple resources, like blood tests and an X-ray, is usually assigned ESI Level 3, while a patient needing only one resource, such as a single prescription, is designated Level 4. A patient requiring no resources and simple advice is classified as Level 5. This method balances the severity of the illness with the anticipated strain on hospital resources.
In mass casualty events, a simpler, color-coded system like Simple Triage and Rapid Treatment (START) is often used to make quicker decisions. This system assesses a patient’s ability to walk, their respiratory status, perfusion (blood circulation), and mental status (RPMs). Patients are tagged with colors:
- Red for immediate transport.
- Yellow for delayed but still serious care.
- Green for minor injuries.
- Black for those deceased or whose survival is not expected given the resource constraints.
Common Misunderstandings About Triage
A frequent source of patient frustration is the misunderstanding that the emergency room operates on a first-come, first-served basis. The reality is that triage is a continuous process of prioritization, meaning a patient arriving later with a higher level of acuity will be seen before a patient who arrived earlier but was categorized as less urgent. This non-sequential order reflects the system’s objective to prevent the death or permanent disability of the most unstable patients.
Patients often confuse the initial triage assessment with the start of definitive treatment or a full medical diagnosis. The Triage Nurse’s role is not to diagnose the condition but to quickly assess the patient’s stability and assign a priority level. This brief evaluation is designed only to determine the safest order of care, not to provide comprehensive medical treatment.
The perception of a long wait time for lower-acuity patients is a direct consequence of the triage system functioning correctly. That delay indicates that the patient is medically stable and that more limited resources are being appropriately directed toward individuals with life-threatening conditions. Triage is a mechanism for safety and resource allocation.