The ankle-brachial index test is a quick, noninvasive way to check your risk of peripheral artery disease (PAD). Peripheral artery disease is a condition in which the arteries in your legs or arms are narrowed or blocked. People with peripheral artery disease are at an increased risk of heart attack, stroke, poor circulation and leg pain.
The ankle-brachial index test compares your blood pressure measured at your ankle with your blood pressure measured at your arm. A low ankle-brachial index number can indicate narrowing or blockage of the arteries in your legs, increasing your risk of circulatory problems, and possibly causing heart disease or stroke.
The ankle-brachial index test is sometimes recommended as part of a series of three tests, including the carotid ultrasound and abdominal ultrasound, to check for blocked or diseased arteries.