ABCD² Score (TIA)
Predict short-term stroke risk after transient ischemic attack.
ABCD² Criteria
ABCD² Score
0
Low risk (~1.0% 2-day stroke risk)
About
The ABCD² score estimates short-term stroke risk after a transient ischemic attack (TIA) from five factors — Age (≥60), Blood pressure (≥140/90), Clinical features (unilateral weakness 2, speech disturbance without weakness 1), Duration (≥60 min 2, 10–59 min 1), and Diabetes (1) — for a total of 0–7, stratified into low (0–3), moderate (4–5), and high (6–7) risk. In the original derivation (Johnston 2007) the 2-day stroke risks were approximately 1.0%, 4.1%, and 8.1% across these bands, with corresponding 7-day and 90-day gradients. It was designed to help triage which TIA patients need the most urgent evaluation. Current caveat: multiple external validations found that ABCD² discriminates stroke risk poorly — particularly when applied by non-specialists — and that it does not reliably separate high- from low-risk patients or identify high-risk causes such as carotid stenosis or atrial fibrillation. Guidelines therefore treat it as a supportive triage aid rather than a stand-alone rule (the AHA/ASA give it a Class IIa role in admission decisions), and many specialists favour urgent specialist assessment and imaging of all TIA patients regardless of score. Use as: a rough early-risk prompt, not a substitute for expedited TIA work-up. If a stroke does occur, its severity is quantified with the NIH Stroke Scale.
Formula
Interpretation
| ABCD² Score | Risk Level | 2-Day Stroke Risk |
|---|---|---|
| 0 – 3 | Low | ~1.0% |
| 4 – 5 | Moderate | ~4.1% |
| 6 – 7 | High | ~8.1% |
2-day risks are from the original derivation (Johnston 2007); external validations show ABCD² discriminates stroke risk poorly, so it is best used as a supportive triage aid — not a stand-alone rule — alongside urgent specialist assessment. A low score does not exclude high-risk causes (e.g., carotid stenosis, atrial fibrillation). If a stroke occurs, grade severity with the NIH Stroke Scale.
References
- Johnston SC, et al. Validation and refinement of scores to predict very early stroke risk after transient ischaemic attack. Lancet. 2007;369(9558):283-292.
- Rothwell PM, et al. A simple score (ABCD) to identify individuals at high early risk of stroke after transient ischaemic attack. Lancet. 2005;366(9479):29-36.
- Perry JJ, et al. Prospective validation of the ABCD2 score for patients in the emergency department with transient ischemic attack. CMAJ. 2011;183(10):1137-1145.
- Easton JD, et al. Definition and evaluation of transient ischemic attack: a scientific statement from the AHA/ASA. Stroke. 2009;40(6):2276-2293.
FAQ
Disclaimer
Educational and informational reference only. Not intended to replace professional medical advice, diagnosis, treatment, or independent verification.