Emergency Severity Index

The Emergency Severity Index (ESI) is a five-level emergency department triage algorithm, initially developed in 1999. It is maintained by the Agency for Healthcare Research and Quality (AHRQ).

ESI triage is based on the acuity of patients' health care problems and the number of resources their care is anticipated to require. This differs from standardized triage algorithms used in several other countries, such as the Australasian Triage Scale, which attempt to divide patients based on the time they may safely wait.

The concept of a "resource" in ESI means types of complex interventions or diagnostic tools, above and beyond physical examination. Examples of resources include X-ray, blood tests, sutures, and intravenous or intramuscular medications. Oral medications and prescriptions are specifically not considered resources by the ESI algorithm.

The ESI levels are numbered one through five, with level one indicating the greatest urgency. The levels are as follows:

Level	Name	Description	Examples
1	Resuscitation	Immediate, life-saving intervention required without delay	Cardiac arrest Massive bleeding
2	Emergent	High risk of deterioration, or signs of a time-critical problem	Cardiac-related chest pain Asthma attack
3	Urgent	Stable, with multiple types of resources needed to investigate or treat (such as lab tests plus X-ray imaging)	Abdominal pain High fever with cough
4	Less Urgent	Stable, with only one type of resource anticipated (such as only an X-ray, or only sutures)	Simple laceration Pain on urination
5	Nonurgent	Stable, with no resources anticipated except oral or topical medications, or prescriptions	Rash Prescription refill

References

Template:Research help Gilboy N, Tanabe T, Travers D, Rosenau AM (2011). Emergency Severity Index (ESI): A Triage Tool for Emergency Department Care, Version 4. Implementation Handbook 2012 Edition. AHRQ. ISBN 978-1-58763-416-1.