The Ankle-Brachial Index (ABI) test is performed by measuring blood pressure at the ankle and in the arm while a person is at rest. The test can also be conducted while exercising, in which case the blood pressure measurements are repeated at both sites after a few minutes of walking on a treadmill.
The ankle-brachial index (ABI) result is used to predict the severity of peripheral arterial disease (PAD). A slight drop in your ABI with exercise means that you may have PAD. This drop may be important, because PAD can be linked to a higher risk of heart attack or stroke.
What is Normal?
A normal resting ABI is 1.0 to 1.4. This means that your blood pressure at your ankle is the same or greater than the pressure at your arm. This suggests that the blood flow is normal and peripheral artery disease is minimal.
Abnormal values for the resting ABI are 0.9 or lower and 1.40 or higher. Abnormal values may mean you have a higher chance of having narrowed arteries in other parts of your body, increasing your risk of a heart attack or stroke.