Ankle-brachial Index (ABI) Test This is a non-invasive test that compares the blood pressure in your ankle with the blood pressure in your arm. A low ankle-brachial index (ABI) number might mean that you have narrowing or blockage of the arteries in your legs. This test is typically used to look for peripheral artery disease (PAD). During an ABI test, your doctor uses a blood pressure cuff and ultrasound to check blood pressure and blood flow. You might be asked to walk on a treadmill and have readings taken before and after exercising so that your doctor can better assess any narrowed arteries. An ABI test generally takes only a few minutes. You don’t need to prepare or recover in any special way. Depending on the results, your Baystate Health heart doctor may recommend additional tests.