How do paramedics triage patients at a major incident?

At a mass casualty incident, paramedics sort patients by urgency instead of treating each one fully. The aim is to do the greatest good for the greatest number when resources are strained. Treatment during triage is minimal, which runs against normal pre-hospital practice, and the goal is to move patients toward more comprehensive care. Each patient gets a visible category, usually a color, and the category is rechecked as things change. Sources: StatPearls on the NCBI Bookshelf. [1]

Responders usually begin with a global sort. Walking casualties are directed to one location away from the incident, and someone is assigned to keep them together. Responders then assess non-ambulatory victims where they lie. Under the national Model Uniform Core Criteria, the first priority for individual assessment is people who cannot follow commands or have an obvious threat to life, such as severe external bleeding. Walking patients still must be assessed individually once resources allow, as a Miami-Dade procedure also stresses ([mdfrems.miamidade.gov](https://mdfrems.miamidade.gov/mobi/_assets/procedure%2035.pdf), [ems.gov](https://www.ems.gov/assets/MUCC_Addendum_EMT.pdf)). [2] [3]

Simple Triage and Rapid Treatment (START) can be used by all personnel regardless of medical training, with each victim triaged in 60 seconds or less. It checks respirations, perfusion and mental status. A breathing rate above 30 per minute is red. A person who is not breathing has the airway opened, and is red if breathing starts or black if not. For perfusion, a missing radial pulse or capillary refill over 2 seconds is red, and life-threatening limb bleeding gets a tourniquet. For mental status, someone who cannot follow commands is red, a non-walking person who follows commands is yellow, and a walking person who follows commands is green. When in doubt, responders assign the more urgent category. Children are assessed with an adaptation called JumpSTART ([mdfrems.miamidade.gov](https://mdfrems.miamidade.gov/mobi/_assets/procedure%2035.pdf)). [2]

The Model Uniform Core Criteria specify five categories: immediate (red), delayed (yellow), minimal (green), expectant (gray) and dead (black). Assessment should use yes-or-no criteria rather than counting or timing vital signs, and should not use diagnostic equipment. Expectant patients have injuries unlikely to be survivable given available resources, and they receive resuscitation or comfort care when resources allow. Lifesaving interventions are done before a category is assigned, but only if they take under a minute, are within the provider's scope and do not require staying with the patient. Examples are controlling severe bleeding, basic airway opening, chest decompression and autoinjector antidotes ([ems.gov](https://www.ems.gov/assets/MUCC_Addendum_EMT.pdf)). [3]

Triage is dynamic. A patient may move to another category as their condition changes, and many triage tags have fold-over tabs for this reason ([ncbi.nlm.nih.gov](https://www.ncbi.nlm.nih.gov/books/NBK459369/)). Other systems exist. England's NHS Major Incident Triage Tool uses a sequence of yes-or-no questions leading to priority levels P1, P2 and P3, or dead ([england.nhs.uk](https://www.england.nhs.uk/long-read/nhs-major-incident-triage-tool-mitt/)). One local guideline describes a sieve followed by a second triage tool used to reassess patients ([rutherfordcountytn.gov](https://rutherfordcountytn.gov/vertical/Sites/%7B0DE57B3C-95FA-46CF-BF78-CE4E5703EB9C%7D/uploads/RCFR_SOG_2025_v1_602.pdf)). The search results give details of only some of these systems, so exact steps vary by region and agency. [1] [4] [5]