Ankle-Brachial Index Test

Test Overview

This test is done by measuring blood pressure at the ankle and in the arm while a person is at rest. Some people also have an exercise test. In this case, the blood pressure measurements are repeated at both sites after a few minutes of exercise, such as walking on a treadmill.

Why It Is Done

This test is done to check for peripheral arterial disease.^{footnote 1}

The test might be done to check your risk of heart attack and stroke.^{footnote 2} The results can help you and your doctor make decisions about how to lower your risk.

Results

The ABI result can help diagnose peripheral arterial disease (PAD). The result can also be used to check your risk of a heart attack and stroke.

Normal

A normal resting ankle-brachial index 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, and suggests that you do not have significant narrowing or blockage of blood flow.^{footnote 3}

Abnormal

A lower ABI means you might have PAD. Abnormal values for the resting ankle-brachial index are 0.9 or lower and 1.40 or higher. If the ABI is 0.91 to 1.00, it is considered borderline abnormal.^{footnote 3}

Abnormal values might mean you have a higher chance of having narrowed arteries in other parts of your body. This can increase your risk of a heart attack or stroke.