Measured Factor Detail
This score estimates the number of days a stroke may occur following a TIA. TIA, also known as mini-stroke, is a temporary loss of brain function resulting from lack of adequate blood and oxygen supply to the brain. During TIA, patients experience signs and symptoms of a stroke, which last for a short period of time. However, a real stroke may occur after a TIA, and the ABCD2 score is used to estimate the risk for this stroke. The risk for stroke depends on age, blood pressure, clinical features, duration of TIA, and presence of diabetes. The ABCD2 score ranges from zero to seven. Age: <60 years = 0 point; ≥60 years = 1 point | BP: systolic BP<140 mmHg and diastolic BP<90 mmHg = 0 point; systolic BP>140 mmHg or diastolic BP>90 mmHg = 1 point | Clinical features: One-sided fragility = 2 points; No fragility along speech disturbance = 1 point; Other symptoms = 0 point | Duration of TIA symptoms: ≥ 60 minutes = 2 points; 10-59 minutes = 1 point; <10 minutes = 0 point | Diabetes: present = 1 point; absent = 0 point.
Emergency Medicine Physician
Measured Factor High Impact
- A score of 1 to 3 (low risk) indicates 2-day risk for stroke is 1%, 7-day risk for stroke is 1.2%, and 90-day risk for stroke is 3.1%
- A score of 4 to 5 (moderate risk) indicates 2-day risk for stroke is 4.1%, 7-day risk for stroke is 5.9%, and 90-day risk for stroke is 9.8%
- A score of 6 to 7 (high risk) indicates 2-day risk for stroke is 8.1%, 7-day risk for stroke is 11.7%, and 90-day risk for stroke is 17.8%
- Patients with high risk of stroke require urgent specialist assessment as soon as possible and within 24 hours.
- Critical High: Score from 6 to 7
- Normal: 0
- Normal Adult Male: 0
- Normal Adult Female: 0
- Normal Geriatric Male: 0
- Normal Geriatric Female: 0
ABCD2 score does not identify some patients with high risk for stroke such as those with carotid stenosis or atrial fibrillation.
Study Validation 1
A systematic analysis reviewed 16 validation studies for the ABCD2 score. In 14 studies reporting 7-day stroke risk, the ABCD2 rule correctly predicts occurrence of stroke at 7 days for low risk, moderate risk, and high risk groups. In 11 studies reporting 90-day stroke risk, the ABCD2 score overpredicted the risk for stroke, e.g. observed 426 strokes versus predicted 626 strokes. The study concluded that the ABCD2 is a useful to predict 7-day risk of stroke.
Study Validation 2
A cohort study of 512 consecutive patients with suspected TIA showed that an ABCD2 score ≥ 5 had modest specificity for stroke within 2 days (0.58) and 90 days (0.58). However, positive predictive values (2 days, 0.03; 90 days, 0.04) and positive likelihood ratios (2 days, 2.40; 90 days, 1.71) were both poor. The study concluded that the ABCD2 score performed poorly, because it did not take into account underlying stroke mechanism such as atrial fibrillation and carotid stenosis.
Study Validation 3
A study from eight Canadian emergency departments with 2056 patients showed that an ABCD2 score > 5 had low sensitivities (31.6% and 29.2%) for stroke at 7 days and at 90 days, respectively. Moreover, an ABCD2 score > 2 had high sensitivity (94.7%) for stroke at 7 days but low specificity (12.5%). The study found the ABCD2 score to be inaccurate.
Study Additional 1
A systematic review and meta-analysis of 29 studies with a total of 13,766 TIA patients showed that the ABCD2 score ≥4 was 86.7% sensitive and 35.4% specific for recurrent stroke within 7 days. Factors causing false positive outcomes include tight carotid stenosis or atrial fibrillation, which are not included in the calculation of ABCD2 score. The study concluded that the ABCD2 score did not distinguish between low risk versus high risk patients, nor identify patients with carotid stenosis or atrial fibrillation who need urgent intervention.