NREMT study guide · EMT level

Stroke Assessment for EMTs: Cincinnati scale, BE-FAST and last known well

By Rounds EMS
Updated September 28, 2026 · 11 min read

Always follow your local protocols. Which stroke scale you use, which hospital you go to and when you call a stroke alert are set by your state, your region’s stroke plan and your medical director. This guide prepares you for the NREMT exam; your protocols decide what you do on a call.

Facial droop, arm drift and slurred speech are the three findings of the Cincinnati Prehospital Stroke Scale, and one abnormal finding is enough to call it positive. On a suspected stroke you have four jobs: find the deficit, pin down the last known well time, check a blood sugar, and get the patient to the right hospital with the team warned.

What a stroke looks like

A stroke is brain tissue losing its blood supply, from a clot or from bleeding. What you see depends on which part of the brain is affected. The national model EMS guideline and the EMT curriculum list these presentations:

Face. Drooping on one side, trouble swallowing, the tongue pushing to one side.
Arms and legs. Weakness or paralysis on one side, numbness, trouble walking.
Speech. Slurred words, the wrong words, or no speech at all.
Mental status. Confusion, restlessness, combativeness, a level of consciousness that is dropping, or coma.
Eyes. Double or blurred vision, trouble seeing, or eyes stuck looking to one side in a patient who cannot follow your exam.
Other. Sudden dizziness or vertigo, severe headache, neck pain or stiffness.

The word that matters is sudden. The CDC list of stroke signs starts every item with it. The stroke exam sits inside your normal medical patient assessment: it belongs in the neurologic check of your primary and secondary assessment, not before the airway.

The Cincinnati Prehospital Stroke Scale

The EMT curriculum lists the Cincinnati Prehospital Stroke Scale first among its stroke alert criteria. It is three items, simplified from the hospital’s NIH Stroke Scale. Any one abnormal item is a positive screen. Test each side against the other, because stroke usually hits one side.

Item	How to test	Abnormal finding
Facial droop	Ask the patient to smile or show their teeth.	One side of the face droops or does not move like the other.
Arm drift	Patient closes their eyes and holds both arms straight out for 10 seconds.	One arm drifts down or cannot be lifted.
Speech	Ask them to repeat “You can’t teach an old dog new tricks.”	Slurred words, wrong words, or unable to speak.

Exam trap: a normal Cincinnati scale does not rule out stroke. In the study that validated it, when a physician scored it, an abnormal item picked up 66% of stroke and mini-stroke (TIA) patients overall and 88% of strokes in the front of the brain. A stroke that shows up as dizziness, balance loss or vision loss can pass all three items.

BE-FAST

BE-FAST is the version the CDC teaches the public. It keeps the face, arm and speech checks and adds two in front, Balance and Eyes, two things the three-item scale never tests. The T, time, drives every decision after the scale.

Letter	How to test	Abnormal finding
B: Balance	Ask if they feel off balance or dizzy. Watch them sit or stand if it is safe.	Sudden dizziness, loss of balance, trouble walking.
E: Eyes	Ask if they have trouble seeing normally.	Sudden trouble seeing, double or blurred vision.
F: Face	Ask them to smile.	One side of the face droops.
A: Arms	Ask them to raise both arms.	One arm drifts downward.
S: Speech	Ask them to repeat a simple phrase.	Speech is slurred or strange.
T: Time	For EMS: find out when they were last normal. (The public version says call 9-1-1.)	Any sign above: act now. For EMS, that means a stroke alert and transport per protocol.

The national model guideline does not require one named scale. It says to use a validated prehospital stroke scale, and it lists smile, arm drift and speech as the items a scale may include. Your protocol picks the tool; write down which one you used.

Large vessel occlusion and stroke severity scales

A large vessel occlusion (LVO) is a clot blocking one of the brain’s big arteries. These strokes may need a hospital that can pull the clot out, called mechanical thrombectomy. That is why a positive stroke screen is not the end of your exam.

The national model guideline asks EMS to also use a validated stroke severity scale, and it does not name one. Its examples of what those scales look at are:

Vision changes. Trouble seeing, or the eyes pulled to one side.
Sensory neglect. The patient ignores one side of their body or the room, as if it is not there.
Aphasia. Trouble producing or understanding language, beyond slurring.

Which severity scale you use, and what score triggers a trip to a thrombectomy-capable center, comes from your regional stroke plan.

Last known well

The national guideline lists it as the first step of treatment

What it is: The last time someone saw the patient at their normal baseline. Not the time symptoms were found.
Why it matters: A positive stroke scale with a last known well under 4½ hours may be eligible for clot-dissolving drugs. A positive severity scale under 24 hours may be eligible for thrombectomy. The hospital makes that call, and the last known well time you give it is what the call is based on.
Woke up with it: The last known well is when they went to bed normal the night before, not the time they woke up with symptoms.
Document: A specific clock time and who told you. “This morning” is not a time. Also note whether they take a blood thinner such as warfarin; the guideline lists it in the history.

Exam trap: the patient was found at 07:00 with weakness and was fine at bedtime at 22:00. The last known well is 22:00. Answers built on the 07:00 discovery time are wrong.

Blood glucose and stroke mimics

Low blood sugar is the first stroke mimic on the national guideline’s list, and it is one you can find with a finger stick. That is why the national guideline tells you to check a blood glucose in every patient with altered mental status or a suspected stroke.

Check: Blood glucose on every suspected stroke, where your protocol lets EMTs check it.
Below 60: Treat the low sugar per protocol first. If the deficit is still there after the sugar is corrected, work it up as a stroke again. Some protocols, and the national hypoglycemia guideline, treat at 60 or below.
60 or above: Do not give glucose unless your protocol treats at exactly 60. Keep treating it as a stroke.
Document: The reading. The guideline counts it as a measure of stroke care quality.

The national model guideline names five stroke mimics to look for. A mimic does not mean you drop the stroke workup; it means you keep it in mind while you do it.

Hypoglycemia. The one your glucometer can catch on scene.
Seizure. Ask about a recent seizure and anything the family saw. The guideline lists recent seizure as history you need.
Sepsis. Look for fever or another sign of a serious infection.
Migraine. Ask about a history of migraines and whether this feels like one.
Intoxication. Alcohol or drugs on scene, in the history, or on the breath.

Exam trap: a normal glucose does not make the patient a stroke, and a stroke scale does not replace the glucose check. Exam-style questions often hand you a normal sugar to take hypoglycemia off the table.

Atypical stroke in older adults

The EMT curriculum flags stroke as common in older patients. The trouble is that a stroke does not always hit the face, arm and speech the scale tests. It can show up as:

Sudden confusion or trouble understanding what is said, with a normal-looking face and grip.
Sudden dizziness, loss of balance, or being unable to walk.
Sudden trouble seeing.
A family report that they are “not acting right.”

The fix is the baseline. Ask the family or caregiver what the patient is normally like and exactly when that changed. An 86-year-old who has had dementia for years is not new. An 86-year-old who was chatting normally 30 minutes ago and now cannot follow a command is sudden. With a normal sugar, you treat it as a possible stroke and keep the other mimics in mind until the hospital rules it out.

Care and transport, step by step

These are the national model guideline’s steps, written for an EMT. Airway, breathing and circulation come first, as with any patient.

Pin down the last known wellA clock time and the source.
Give oxygen only if neededThe target is a saturation of 94–98%. A patient already in that range does not need it.
Check the blood glucoseTreat only if it is below 60 mg/dL.
Run your stroke scale and severity scaleRecord which scale you used and what you found.
Notify the hospital earlyPer your local stroke plan, including any suspected large vessel occlusion. The guideline tracks how early the stroke team was alerted.
Position to prevent aspirationHead of the stretcher up 15–30 degrees if the systolic blood pressure is above 100, with the head and neck kept straight.
Protect the weak sideA paralyzed arm or leg can be injured without the patient feeling it.
Transport to the right hospitalKeep scene time short. Your stroke plan decides between a stroke-ready hospital, a primary stroke center, a thrombectomy-capable center or a comprehensive stroke center.

Exam trap: the closest hospital is not automatically the right one. When the question tells you the patient has a large vessel occlusion picture and a short last known well, look for the answer that follows the stroke plan to a center that can do thrombectomy.

What not to do

Do not treat the high blood pressure. The national guideline says it outright. Blood pressure is the hospital’s call.
Do not give glucose for a normal sugar. Treat only below 60 mg/dL.
Do not give aspirin unless your protocol says to. Aspirin is an EMT drug for suspected heart attack. It is not in the stroke guideline, and a stroke can be a bleed, which you cannot tell apart from a clot in the field.
Nothing by mouth, per protocol. Stroke can take away the ability to swallow, and aspiration is the guideline’s first safety concern.
Do not stay on scene to finish a long exam. The guideline measures scene time. Do the scale, the sugar and the time, then move.

Try one from the Rounds bank

A real atypical stroke question

You are called for an 86-year-old patient who is “not acting right.” Family reports the patient was normal 30 minutes ago but is now confused and having difficulty following commands. The patient has equal grip strength, clear speech, no facial droop, and a blood glucose level of 112 mg/dL.

Which is the MOST likely explanation?

Medication-induced altered mental status
Delirium secondary to an infection
A postictal state following an unwitnessed seizure
An atypical presentation of an acute stroke

Show the answer

D. An atypical presentation of an acute stroke. The clues are a sudden change from a normal baseline 30 minutes ago, trouble following commands, and a normal blood sugar. There is no droop, drift or slurring, but older adults can have a stroke that shows up only as confusion. Treat it as a time-sensitive stroke.

B is the tempting one: infection often causes confusion in older adults, but it usually builds over hours to days, not 30 minutes. C needs something pointing to a seizure, and nothing does. A needs a link to a medication change or dose error, and the question gives none.

A normal Cincinnati scale does not rule out stroke. Sudden onset with a normal glucose means you treat it as a possible stroke.

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Frequently asked questions

What is the Cincinnati Prehospital Stroke Scale?

A three-item stroke screen: facial droop, arm drift and speech. You ask the patient to smile, hold both arms out with eyes closed for 10 seconds, and repeat a phrase. Any one abnormal item is a positive screen.

What does BE-FAST stand for?

Balance, Eyes, Face, Arms, Speech, Time. It adds balance and vision checks to the face, arm and speech checks, and the T means call for help and note the time right away.

What is last known well in a stroke patient?

The last time someone saw the patient at their normal baseline. If they woke up with symptoms, it is when they went to bed normal, not when they woke up. Record a specific time and who gave it to you.

Why do EMTs check blood sugar on a possible stroke?

Low blood sugar is a stroke mimic, and it is fixable on scene. The national model guideline says to check it on every suspected stroke and to treat only if it is below 60 mg/dL.

Can a patient have a stroke with a normal stroke scale?

Yes. The three-item scale misses some strokes, especially ones that cause dizziness, balance or vision loss. Older adults may show only sudden confusion. A sudden change with a normal blood sugar means you treat it as a possible stroke and keep the other mimics in mind until the hospital rules it out.

Sources

Scale items, time windows and treatment steps on this page were checked against these documents. Question counts come from the Rounds EMS question bank as of September 27, 2026.

National Model EMS Clinical Guidelines, Version 3.0. NASEMSO, 2022.
National EMS Education Standards: Emergency Medical Technician Instructional Guidelines. NHTSA, 2009.
Signs and Symptoms of Stroke. Centers for Disease Control and Prevention, 2026.
Cincinnati Prehospital Stroke Scale: reproducibility and validity. Kothari RU et al., Annals of Emergency Medicine, 1999.

Please follow your local protocols and your medical director’s orders. This guide is for exam study only and does not replace them.