Emergency Severity Index, Version 4

The Emergency Severity Index Version 4 Triage Algorithm, implementation handbook, and training DVDs are available at no charge from the Agency for Healthcare Research and Quality at

The ESI version 4 algorithm is copyrighted and is the intellectual property of the ESI Triage Research Team, LLC. The algorithm may not be changed in any way by any user. The algorithm and the contents of the DVD set and implementation handbook may be incorporated into additional training materials developed by a user, on the condition that no fee is charged by the user for the Algorithm, the contents of the ESI Handbook, or the additional training materials in the DVDs.