Neurology

ABCD² Score Calculator for TIA Stroke Risk

Stroke risk assessment in the first 2-7 days after TIA

Primary source: Johnston SC et al. Lancet 2007; 369(9558): 283-292

Aleksandr A. Aulov, MD, internal medicine Last clinical review: April 28, 2026

Online calculation

Age ≥ 60 years

Blood pressure: SBP ≥ 140 and/or DBP ≥ 90 mm Hg

Clinical features of TIA

Duration of TIA

Diabetes mellitus

About this score

ABCD² is a clinical scale for estimating the risk of ischemic stroke in the 7 days following a transient ischemic attack (TIA). It was developed by S. Johnston et al. (Lancet, 2007) based on data from more than 4,000 patients. The acronym stands for Age, Blood pressure, Clinical features, Duration, and Diabetes.

Parameters: age ≥ 60 years (1 point), BP ≥ 140/90 (1 point), unilateral motor deficit (2 points) or speech disturbance without motor deficit (1 point), duration ≥ 60 min (2 points) or 10-59 min (1 point), diabetes mellitus (1 point). Total score 0-7. Stratification: 0-3, low risk (~1% at 7 days); 4-5, moderate risk (~4%); 6-7, high risk (~8%).

Current guidelines (AHA 2021) have shifted from using ABCD² purely as a predictive tool toward urgent work-up of all high-risk TIA patients within the first 24 hours, regardless of ABCD² score. The scale nevertheless remains useful for documentation and screening in outpatient practice.

When to use

Patient with suspected TIA: assessment of short-term stroke risk.
Triage decision: urgent TIA clinic versus hospital admission.
Documenting the clinical rationale for outpatient management.
Screening in general practice to identify high-risk patients.

Clinical example

Case

A 72-year-old man presented 6 hours after an episode of right-sided arm and leg weakness lasting about 90 minutes. Blood pressure on admission 165/95, type 2 diabetes mellitus on insulin, neurologic exam fully normalized at the time of evaluation.

Calculation

Age ≥ 60 (1) + BP ≥ 140/90 (1) + unilateral motor deficit (2) + duration ≥ 60 min (2) + diabetes (1) = 7 points.

Interpretation and management

Very high risk (~8% stroke risk within 7 days). Management: immediate admission, urgent neuroimaging (CT or MRI), carotid duplex ultrasound and/or CT angiography, echocardiography, Holter monitoring to screen for atrial fibrillation, initiation of antiplatelet therapy (aspirin loading dose 300 mg, followed by clopidogrel or ticagrelor plus aspirin for a short period per guidelines), statin therapy, and blood pressure control.

Limitations and cautions

Current guidelines require urgent work-up of ALL TIA patients within 24 hours, regardless of ABCD² score.
The scale poorly stratifies patients with symptomatic carotid stenosis, in whom stroke risk is high regardless of other factors.
Patients with atrial fibrillation have high risk that is not captured by the scale.
Not applicable after a stroke has already occurred; it predicts future stroke risk rather than assessing an existing deficit.

Related calculators

Frequently asked questions

Can ABCD² be used to decide between outpatient management and hospital admission?

Not under current practice. All TIA patients should undergo urgent work-up within the first 24 hours. ABCD² is used as an adjunct documentation tool.

What counts as a 'motor deficit'?

Weakness of the arm, leg, or one side of the body, reported as obvious by the patient or a witness. Isolated numbness without weakness does not count.

Is ABCD² applicable when a brainstem event is suspected?

With caution. Brainstem symptoms (diplopia, vertigo, dysarthria) are poorly captured by the scale and may underestimate risk.

Are there modified versions of ABCD²?

Yes: ABCD³ (adds a second TIA within the past week) and ABCD³-I (adds neuroimaging findings). These are more accurate but less widely used.

All clinical calculators in one place

Validated scores and formulas with full interpretation, clinical examples and source references. Open access, no registration required.

65+ calculators · scores and formulas · interpretation with management notes

Browse all calculators

АА

Aleksandr A. Aulov Physician, internal medicine, Sechenov School — independent medical education platform. Calculators are compiled from the original publications and current clinical guidelines. Interpretation thresholds follow the source study unless stated otherwise.

This calculator is intended for healthcare professionals. Do not use it for self-diagnosis or self-treatment. Management decisions are made by the treating clinician based on the full clinical picture of the individual patient.