ABCD2 Stroke Risk Calculator

The ABCD2 score is a clinical prediction tool that estimates the short-term risk of stroke after a transient ischemic attack (TIA). It adds points for five factors: age, blood pressure, clinical features, symptom duration, and diabetes, for a total of 0 to 7. It was published by Johnston and colleagues in The Lancet in 2007 and is widely used to help triage patients after a suspected TIA.

You add up to 7 points across five items. Age 60 or older scores 1 point, and a blood pressure of 140/90 mmHg or higher (systolic at least 140 or diastolic at least 90) scores 1 point. Unilateral weakness scores 2 points and speech disturbance without weakness scores 1 point, while symptoms lasting 60 minutes or more score 2 points and 10 to 59 minutes scores 1 point. Diabetes adds 1 point.

Scores fall into three bands. A score of 0 to 3 is low risk, with roughly a 1.0% stroke risk at 2 days, 1.2% at 7 days, and 3.1% at 90 days. A score of 4 to 5 is moderate risk (about 4.1%, 5.9%, and 9.8%), and a score of 6 to 7 is high risk (about 8.1%, 11.7%, and 17.8%). These percentages come from the original 2007 validation cohort.

Duration is how long the TIA symptoms lasted before they resolved: 60 minutes or longer scores 2 points, 10 to 59 minutes scores 1 point, and under 10 minutes scores 0. For clinical features, unilateral weakness (one-sided weakness of the face, arm, or leg) scores 2 points, speech disturbance without any weakness scores 1 point, and any other symptom scores 0. Use the single feature that gives the highest points.

Clinicians use it alongside the full clinical picture to judge how urgently to evaluate someone after a suspected TIA. Higher scores have historically prompted faster imaging, specialist referral, and admission, though many stroke services now assess and image everyone urgently regardless of score. The score supports triage but does not replace clinical judgment, vascular imaging, or guideline-based care.

No. This calculator is for education and quick reference only and is not a substitute for professional medical advice, diagnosis, or treatment. A TIA is a medical emergency, so if you or someone else has sudden stroke-like symptoms, call emergency services right away. Only a qualified clinician can interpret the score in the context of the full evaluation.