Medical AIABCD2 score for stroke risk after TIA
A 7-point score (0 to 7) estimating the 2-day risk of stroke after a transient ischaemic attack, from age, blood pressure, clinical features, symptom duration, and diabetes. Higher scores predict higher early stroke risk, but current guidance increasingly favours urgent specialist assessment and imaging over the score alone.
How to measure each input
- Age and diabetes
- Age of 60 years or older scores 1, and a history of diabetes mellitus scores 1.
- Blood pressure
- Use the first recorded blood pressure after the event. A systolic of 140 mmHg or more, or a diastolic of 90 mmHg or more, scores 1.
- Clinical features
- Score only the highest-value feature: unilateral weakness scores 2, isolated speech disturbance without weakness scores 1, and other symptoms (for example isolated sensory or visual symptoms) score 0.
- Duration
- Total symptom duration: 60 minutes or more scores 2, 10 to 59 minutes scores 1, and under 10 minutes scores 0.
Interpretation
| Band | Meaning |
|---|---|
| 0 to 3, low risk | In the original validation, the 2-day stroke risk was about 1.0% in this band. Low does not mean no risk: all suspected TIA still warrants prompt assessment, antithrombotic therapy where appropriate, and risk-factor management. |
| 4 to 5, moderate risk | The 2-day stroke risk was about 4.1% in this band. Arrange urgent specialist assessment and investigation, including brain and carotid imaging. |
| 6 to 7, high risk | The 2-day stroke risk was about 8.1% in this band. Treat as high priority for immediate specialist evaluation, imaging, and secondary prevention. |
Pitfalls, exclusions and caveats
- Current guidance increasingly favours urgent specialist assessment and brain/carotid imaging over the ABCD2 score alone; the score should not be used to defer or deny rapid evaluation in a suspected TIA.
- The score does not capture key high-risk features such as atrial fibrillation, significant carotid stenosis, or crescendo TIAs, which warrant urgent action regardless of the score.
- It depends on an accurate TIA diagnosis. Mimics (migraine aura, seizure, syncope, hypoglycaemia) inflate or distort the score and the apparent risk.
- Score only the single highest-value clinical feature and a single duration band; double-counting overestimates the total.
- The published 2-day risks are population averages from validation cohorts and may not match an individual patient's risk.
Age >= 60 years (1) + Blood pressure >= 140/90 mmHg at presentation (1) + Clinical features (unilateral weakness 2, speech disturbance without weakness 1, other 0) + Duration (>= 60 min 2, 10 to 59 min 1, < 10 min 0) + Diabetes (1). Total 0 to 7.The ABCD2 score was described by Johnston et al. (2007). This implementation is an educational tool and is not affiliated with the original authors or any guideline body.
Frequently asked
What is a high-risk ABCD2 score?
A score of 6 to 7 carried about an 8.1% 2-day stroke risk in the original validation, 4 to 5 about 4.1%, and 0 to 3 about 1.0%. Scores of 4 or more are generally considered to need the most urgent assessment.
Should I use ABCD2 to decide whether to refer a TIA urgently?
Modern guidance favours urgent specialist assessment and imaging for all suspected TIA rather than relying on the ABCD2 score to triage. The score can describe risk but should not be used to delay or withhold rapid evaluation, especially with features like atrial fibrillation or carotid stenosis.
How do I score the clinical features and duration?
Take only the single highest-value clinical feature (unilateral weakness 2, isolated speech disturbance 1, other 0) and a single duration band (>= 60 minutes 2, 10 to 59 minutes 1, < 10 minutes 0). Do not add multiple features or durations together.
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