The ankle brachial index (ABI) is a measurement that is useful to your physician in evaluating the adequacy of the circulation in your legs. It is a noninvasive test to check your risk of peripheral artery disease. Patients with peripheral artery disease could be at risk for heart disease, poor circulation or stroke. To obtain the ABI, your technician measures the blood pressure in your legs and arms. This procedure will pinpoint if there is a segment in your legs that could indicate a narrowing or blockage.