Major incident triage tools

Classification: Official
Publication reference: PRN00358_i

To: NHS ambulance service chief executives
cc. NHS England regional heads of emergency preparedness, resilience and response (EPRR)

Dear colleagues

Major incident triage tools

We are writing to inform you of a new development in major incident casualty triage and to request your organisation’s endorsement of the triage tool to be used by any responder who may be involved in a major incident.

As part of a review of major incident triage undertaken by the NHS England Emergency Preparedness, Resilience and Response (EPRR) Clinical Reference Group, two new triage tools have been developed. Those are the NHS Major Incident Triage Tool (MITT), to be used by all NHS responders, and the Ten Second Triage tool (TST), intended to be used by anyone responding to a major incident to provide care to casualties prior to the arrival of the NHS clinical response. A paper was presented to the National Ambulance Service Medical Directors (NASMeD) group in October 2022 by the National Ambulance Resilience Unit (NARU) medical advisor. The new tools will be incorporated into the Joint Royal Colleges Ambulance Liaison Committee (JRCALC) guidelines and app and the TST will be incorporated into the Joint Emergency Services Interoperability Principles (JESIP) app.

NHS Major Incident Triage Tool (MITT)

The MITT will be a single tool for both adult and paediatric patients at the scene of a major incident and allows for rapid, reliable and reproducible triage. In comparison with other triage tools the MITT demonstrates an increased sensitivity and reduced rate of under-triage in those patients requiring lifesaving interventions. MITT will replace the current triage sieve tool, the triage sort tool and the paediatric triage tape.

MITT has been derived from the Modified Physiological Triage Tool-24 (MPTT), which is included in the NHS England Clinical Guidelines for Major Incidents and Mass Casualty Events. Evidence demonstrated that the current triage sort tool performs poorly compared to MPTT at identifying patients in need of lifesaving intervention therefore the consensus decision was taken to remove and replace with repeat iterations of triage using MITT and senior clinical decision makers. This will be supplemented by local major trauma processes when resources allow.

MITT has undergone extensive field testing across a number of scenarios with a range of responders and with input from behavioural science, including quantitative and qualitative feedback from end users.

Ten Second Triage (TST)

The TST is designed to be quick, simple and effective at prioritising large numbers of casualties rapidly with a focus on immediately providing lifesaving interventions (LSI). These LSI include control of severe bleeding and opening of the airway, which are known to be the key requirements to maximise patient survival in the early stages of injury.

The simplicity of the tool minimises cognitive burden and frees up bandwidth to assist responders to treat casualties in what will be very challenging circumstances.

There are no physiological parameters; breathing and pulse rate are not measured allowing the tool to be used by those responders with little or no clinical training. In addition, the tool does not triage casualties to dead but labels as not breathing, allowing for appropriate interventions, such as recovery position or CPR, depending on the circumstances until formal triage by a registered healthcare professional.

The TST tool has undergone extensive field testing with a wide range of responders and clinical skillsets and experience. The testing covered incident scenarios with blunt and penetrating trauma, blast, ballistic and burns injuries. Speed and accuracy of triage was similar for all users and allowed the prompt application of LSI. Feedback reinforced that it provided a shared mental model and common language, consistent with the Joint Emergency Services Interoperability Principles (JESIP). The results of research into both tools have been presented at a number of clinical conferences and shared widely.

The ability for all responders to collaborate at scene to save lives and prioritise casualties will likely have significant survival benefits. This was highlighted during the Public Inquiry into the terrorist attack on Manchester Arena on 22 May, 2017, during evidence relating to the ‘care gap’ (volume 2 report, part 20) and incorporated into recommendations 112 and 113. The TST has been recommended for use by all organisations who may be at the scene of or required to respond to a major incident.

Next steps

The tools have been made available from April 2023 with full implementation and replacement of previous triage methodologies across the NHS by 30 June 2024. Education and supporting materials will be made freely available to support wider adoption through the NHS England website. Health colleagues in the Devolved Administrations have indicated an intention to support MITT and TST.

If you require any further information, please contact Mark Sewell at

Yours sincerely,

Professor Chris Moran MD FRCS, National Strategic Incident Director NHS England.

Stephen Groves, Director of Emergency Preparedness, Resilience and Response, NHS England.