FAST-ED is a prehospital stroke severity scale used by EMS to help identify patients who may have a large vessel occlusion stroke (LVO/LVOS) and therefore may need rapid transport to a comprehensive stroke center for possible thrombectomy. It was introduced in 2016 as a simple field tool for triage.

The name stands for Field Assessment Stroke Triage for Emergency Destination. The scale is based on stroke exam findings including facial palsy, arm weakness, speech changes, eye deviation, and denial/neglect. Scores are higher when these findings are more severe, and higher scores mean a greater likelihood of LVO.

In simple terms, FAST-ED helps answer: “Does this suspected stroke patient need to go straight to a center that can do endovascular treatment?” That is why it is mainly used in the ambulance or other prehospital settings, not as a diagnosis by itself.

Published and public FAST-ED materials often group risk like this:

• score 0–1: low likelihood, usually under 15%
• score 2–3: intermediate likelihood, about 30%
• score 4 or more: high likelihood, roughly 60–85%

It is a triage tool, not a substitute for brain imaging or specialist evaluation. A patient can still have stroke without a high FAST-ED score, and a high score does not prove LVO by itself. Recent field studies suggest it has useful sensitivity for triage, but performance varies by setting.