Stroke Recognition: FAST and BE-FAST for Paramedics

Why Stroke Recognition Matters in Pre-Hospital Care

Stroke is a time-critical medical emergency. In the UK, approximately 100,000 people suffer a stroke each year, and outcomes are directly linked to how quickly treatment begins. For paramedics, the ability to rapidly recognise a stroke, communicate findings clearly, and initiate an appropriate care pathway can mean the difference between full recovery and permanent disability — or death.

As a student paramedic, building a solid understanding of stroke recognition tools is essential not only for your clinical placements but for your written and practical assessments. This article explores the FAST and BE-FAST mnemonics in the context of UK pre-hospital care, drawing on JRCALC guidelines and NHS stroke pathways.

The FAST Mnemonic: The Foundation of Public and Clinical Awareness

The FAST acronym has been widely promoted across the UK through NHS and Stroke Association public health campaigns. It remains a cornerstone of initial stroke recognition and is embedded in pre-hospital practice:

• F — Face: Ask the patient to smile. Is there facial drooping or asymmetry? A unilateral droop strongly suggests upper motor neurone involvement consistent with stroke.
• A — Arms: Ask the patient to raise both arms and hold them outstretched. Pronator drift or unilateral weakness is a key indicator. This tests for contralateral limb weakness due to disruption of the corticospinal tract.
• S — Speech: Is speech slurred, absent, or confused? Assess for dysarthria (motor speech difficulty) or dysphasia (language impairment). Both may be present depending on the area of the brain affected.
• T — Time: Note the time of symptom onset — or the last time the patient was known to be well. This is critical for determining eligibility for thrombolysis or thrombectomy at a hyperacute stroke unit (HASU).

FAST is simple, quick, and has high public recognition. However, research has demonstrated that it misses a significant proportion of strokes — particularly those involving the posterior circulation.

BE-FAST: Improving Sensitivity for Posterior Circulation Strokes

The BE-FAST mnemonic builds on FAST by adding two additional assessments at the beginning. Studies suggest BE-FAST can identify up to 96% of strokes, compared to approximately 79% with FAST alone. The additional components are particularly valuable for detecting vertebrobasilar strokes, which can present very differently from anterior circulation events.

• B — Balance: Has the patient experienced a sudden loss of balance or coordination? Ataxia, unsteady gait, or dizziness with a new onset may indicate cerebellar or brainstem involvement. Ask witnesses if the patient collapsed or became suddenly unsteady.
• E — Eyes: Are there any sudden visual disturbances? This includes diplopia (double vision), visual field defects such as homonymous hemianopia, or sudden monocular blindness (amaurosis fugax — which may indicate a TIA rather than established stroke). Ask the patient directly about changes in vision.
• F — Face
• A — Arms
• S — Speech
• T — Time

For UK student paramedics, it is worth noting that while FAST remains the dominant public-facing tool, BE-FAST is increasingly referenced in clinical education as a more comprehensive screening approach. Familiarise yourself with both and understand the clinical rationale behind each component.

JRCALC Guidance and the Pre-Hospital Stroke Pathway

The Joint Royal Colleges Ambulance Liaison Committee (JRCALC) clinical guidelines provide the evidence base for UK paramedic practice. In the context of stroke, key considerations include:

• Identifying stroke and TIA using validated screening tools
• Establishing the time of symptom onset or last known well time
• Performing blood glucose measurement to exclude hypoglycaemia as a stroke mimic
• Assessing and maintaining the airway, particularly in patients with reduced consciousness
• Providing a pre-alert to the receiving hospital — ideally a designated HASU or stroke centre
• Avoiding unnecessary on-scene delays; the target is rapid transport to a specialist centre

Blood glucose must always be measured. Hypoglycaemia is the most common and dangerous stroke mimic in pre-hospital care, and it is entirely reversible with prompt treatment. Failing to check BM before assuming a neurological diagnosis is a significant clinical error.

Stroke Mimics: What Else Could It Be?

Not every patient presenting with focal neurological signs is having a stroke. Stroke mimics account for a meaningful proportion of pre-hospital stroke calls. Common differentials to consider include:

• Hypoglycaemia
• Todd's paresis (post-ictal focal weakness following a seizure)
• Hemiplegic migraine
• Hypertensive encephalopathy
• Space-occupying lesions (e.g., brain tumour or subdural haematoma)
• Functional neurological disorder

In the pre-hospital environment, your role is not to definitively diagnose — it is to recognise, stabilise, and expedite. However, a thorough history and an awareness of mimics will support more accurate clinical decision-making and better handover communication.

Key Assessment Points in Practice

When assessing a suspected stroke patient on scene, structure your approach to capture the information that will matter most to the receiving team:

1. Establish the exact time of symptom onset or last known well time
2. Perform and document a FAST or BE-FAST assessment
3. Measure and record blood glucose
4. Obtain a 12-lead ECG — atrial fibrillation is a major cause of cardioembolic stroke
5. Assess GCS and document baseline neurological observations
6. Take a focused history including anticoagulant use, recent surgery, and prior strokes or TIAs
7. Provide an early pre-alert to the receiving HASU

Clear, structured communication using tools like SBAR (Situation, Background, Assessment, Recommendation) ensures the stroke team can prepare appropriately before the patient arrives — saving vital minutes in the door-to-needle or door-to-thrombectomy process.

TIA: Don't Underestimate the Warning Shot

A transient ischaemic attack (TIA) resolves completely within 24 hours, but it carries a significant short-term risk of full stroke — particularly in the first 48 hours. UK guidance supports urgent same-day assessment for high-risk TIA patients. As a paramedic, treat a suspected TIA with the same urgency as an established stroke until proven otherwise, and avoid advising patients to simply "wait and see" their GP.