As an investigator-initiated and conducted, multi-centre, open-label, single-arm prospective observational trial, INTERACT4 Expansion aims to evaluate the diagnostic accuracy of GFAP measured using a point-of-care device, for identifying ICH in participants presenting with acute stroke-like symptoms in the pre-hospital setting compared with imaging-confirmed ICH.

Inclusion Criteria:

1. Adults (age ≥18 years);
2. Acute syndrome that is due to presumed acute stroke, defined as FAST (Face, Arm, Speech, Time) scores of ≥2 with an arm motor deficit;
3. Time ≤3 hours from last seen well;
4. Systolic BP (SBP) ≥150mmHg.

Exclusion Criteria:

1. Participants in coma (no response to tactile/verbal stimulation); or/and do not respond to "P" or "U" on the alert/verbal/painful/unresponsive (APVU) responsiveness scale;
2. Severe known co-morbid disease (e.g. cancer, chronic airflow disease, severe dementia, severe heart failure, pre-existing disability [needing help]);
3. Known history of epilepsy or seizure at onset;
4. Recent head injury (where there is potential for another type of intracranial haemorrhage or head trauma);
5. Hypoglycaemia (glucose<4.0 mmol/L) as measured in the ambulance.

Patients with suspected acute stroke presenting to ambulance services