ABCD² Score Calculator (TIA Stroke Risk)
Early stroke risk after a transient ischaemic attack with the ABCD² score — age, blood pressure, clinical features, duration and diabetes — 2-day, 7-day and 90-day stroke risk.
How it works
Age ≥ 60 1 + BP ≥ 140/90 1 + Clinical: weakness 2 / speech only 1 + Duration ≥ 60 min 2 / 10–59 min 1 + Diabetes 1 (max 7)
About one in twenty people who have a transient ischaemic attack suffer a completed stroke within a week, and the risk is front-loaded into the first 48 hours. The ABCD² score was derived to identify who is most at risk so they can be imaged, started on antiplatelets and, if carotid stenosis is found, offered urgent endarterectomy. Unilateral weakness and symptoms lasting an hour or more carry two points each. Scores of 4 or more (moderate to high) have traditionally triggered same-day assessment. Newer guidelines, including NICE 2019, recommend that every suspected TIA be seen within 24 hours regardless of score, because the score misses some high-risk mechanisms such as atrial fibrillation and symptomatic carotid disease.
Worked example
A 66-year-old with 30 minutes of right-arm weakness and blood pressure 150/92, no diabetes: 1 + 1 + 2 + 1 = 5 — moderate risk, about 4% stroke risk within 48 hours; same-day assessment.
Frequently asked questions
What is ABCD³-I?
An extension adding dual TIA (another TIA within 7 days, 2 points) and imaging findings (ipsilateral carotid stenosis ≥ 50%, 2; DWI abnormality, 2) for a 13-point score that predicts better.
Does a low score mean the TIA can wait?
Current guidance says no — arrange specialist review within 24 hours for all suspected TIAs and start aspirin 300 mg immediately unless contraindicated.
Related calculators
Clinical decision tool for education and for use by trained clinicians alongside judgement — not a diagnosis and not a substitute for medical assessment. Scores validated in specific populations may not apply to every patient.