ABCD² Score Calculator for TIA
Estimate the short-term risk of stroke after a transient ischaemic attack (TIA) with the ABCD² score. Five features — Age, Blood pressure, Clinical features, Duration and Diabetes — give a total of 0 to 7, and the score sorts patients into low, moderate and high risk over the following two days. Select the features that apply.
About the ABCD² score
The ABCD² score estimates the risk of stroke in the days after a transient ischaemic attack, to help prioritise assessment. Source: 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.
How this is calculated
| Factor | Points |
|---|---|
| Age 60 or over | 1 |
| Blood pressure ≥ 140/90 mmHg | 1 |
| Clinical: unilateral weakness / speech disturbance only / other | 2 / 1 / 0 |
| Duration: ≥ 60 min / 10–59 min / < 10 min | 2 / 1 / 0 |
| Diabetes | 1 |
| Maximum | 7 |
Add the points for each feature. Risk groups: 0–3 low (≈ 1.0% 2-day stroke), 4–5 moderate (≈ 4.1%), 6–7 high (≈ 8.1%). Source: Johnston SC et al., Lancet 2007;369(9558):283–292.
Frequently asked questions
What does ABCD² stand for?
ABCD² is a mnemonic for its five components: Age 60 or over (1 point); Blood pressure of 140/90 mmHg or higher at first assessment (1 point); Clinical features — unilateral weakness (2 points) or speech disturbance without weakness (1 point); Duration — 60 minutes or more (2 points) or 10–59 minutes (1 point); and Diabetes (1 point). The maximum is 7. The superscript 2 marks the two items — clinical features and duration — that can score two points.
What are the ABCD² risk groups?
A score of 0–3 is low risk, 4–5 is moderate and 6–7 is high risk. In the derivation the 2-day stroke risk was about 1.0% in the low group, 4.1% in the moderate group and 8.1% in the high group. Higher scores have historically been used to prioritise urgent specialist assessment and imaging, though many services now assess all suspected TIAs urgently regardless of score.
How is duration measured?
Use the duration of the longest TIA symptom episode: 60 minutes or more scores 2, 10 to 59 minutes scores 1, and under 10 minutes scores 0. If symptoms are still present it is not a TIA (which by definition resolves), and the presentation should be treated as a possible acute stroke. Duration is scored alongside age, blood pressure, clinical features and diabetes, and is one of the two components — with clinical features — that can contribute 2 of the score’s maximum 7 points.
Does a low ABCD² score rule out stroke?
No — the score has only moderate discrimination and a low score does not exclude an early stroke, so it should not be used on its own to defer assessment. Current UK NICE guidance, for example, recommends specialist review within 24 hours for anyone with a suspected TIA irrespective of the ABCD² score. Use it as one input, not a discharge rule.
When should it not be relied on?
ABCD² estimates early stroke risk after a suspected TIA and is not a diagnosis. It does not identify the cause (such as carotid stenosis or atrial fibrillation), which still needs investigation, and it performs less well in non-specialist hands. This is an educational reference, not medical advice.
This is a reference tool, not a diagnosis or medical advice. Results depend on the laboratory, assay and clinical context, and reference intervals vary between labs and by age and sex — always read your result against the range printed on your own report and discuss it with a qualified healthcare professional.
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