What Is an ABI Test? The Leg Circulation Check Most People Have Never Heard Of

Ask most people about heart screenings and they'll mention an EKG or cholesterol. Very few have heard of the ABI test, even though it's one of the simplest ways to check the circulation in your legs.

What does ABI stand for?

ABI stands for ankle-brachial index. "Brachial" refers to the upper arm. The test compares the blood pressure at your ankles with the blood pressure in your arms.

Why compare ankles and arms?

In healthy arteries, blood pressure at the ankle is about the same as, or a little higher than, the pressure in the arm. If the arteries to the legs are narrowed by plaque, less blood gets through and the ankle pressure drops. The ratio between the two numbers gives a simple picture of how well blood is reaching your legs.

What is the ABI looking for?

The main condition the ABI screens for is peripheral artery disease (PAD), a narrowing of the arteries outside the heart, most often in the legs. PAD affects millions of Americans, and many people with it have no symptoms or mistake leg discomfort for normal aging. Because PAD is caused by the same plaque buildup that affects heart and brain arteries, it can also be a signal worth discussing with your doctor about your overall cardiovascular health.

How the test is done

• You lie down and rest for a few minutes.
• Blood pressure cuffs are placed on both arms and both ankles.
• The cuffs inflate one at a time, like a normal blood pressure check, while the pressures are recorded.
• The machine calculates the ratio for each leg.

It's painless and takes only a few minutes. You just lie back and relax.

What the numbers generally mean

• About 1.0 to 1.4: generally considered within the normal range.
• 0.91 to 0.99: borderline.
• 0.90 or lower: may suggest PAD and is worth follow-up with a physician.
• Above 1.4: can mean the arteries are stiff, which can make the reading less reliable.

Your results are always interpreted by a physician in the context of your full screening. At ProActive Health Screening, a board-certified cardiologist reviews your results.

Who might consider an ABI?

People often consider it if they are over 50, smoke or used to smoke, have diabetes, high blood pressure or high cholesterol, have a family history of vascular disease, or notice leg cramping when walking that eases with rest. If you have symptoms, talk with your doctor.

ABI as part of a full screening

In our Tustin clinic, the ABI is one of four screenings in a 60-minute visit, alongside an EKG, a carotid artery ultrasound and an abdominal aorta ultrasound.

Frequently asked questions

Does the ABI test hurt?

No. It feels like a standard blood pressure check, done on your arms and ankles.

How long does it take?

Usually about 10 minutes, including rest time.

Do I need to do anything to prepare?

Wear loose pants or shorts so your ankles are easy to reach.

Want to know how well your circulation is flowing? Book your screening at proactivescreen.com.

This article is for general education and isn't medical advice. Talk with your doctor about which screenings are right for you.