The ankle-brachial index is a noninvasive test for peripheral artery disease. Easy to perform, quick and painless, it is a common and favored test amongst physicians and patients. Peripheral artery disease is a narrowing of the arteries leading to the limbs of the body, this arrowing constricts blood flow and increases the risk for heart attack and a number of chronic conditions. The ABI Test measures blood pressure in the lower extremities near the ankle and compares the outcome with measurements of blood pressure in the arm.  Vascular and Cardiovascular doctors use this test on patients who have symptoms of PAD and are at high risk for developing the disease. PAD affects 10 percent of the adult population over 55 years of age; people who use tobacco, have diabetes, high blood pressure, high cholesterol are at a higher risk.  Because the test is measured at he ankle you will need to wear accessible clothing, and rest for 10-30 minutes prior to the test to have accurate results.  The test is pain free and will not cause any side effects.