Your Ankle-Brachial Index (ABI): The Complete Guide

If your provider has recommended an Ankle-Brachial Index (ABI) test, you may be wondering what it involves and why it matters. This guide from Southeast Medical Group explains everything you need to know about this simple, non-invasive screening for peripheral artery disease.

What Is an Ankle-Brachial Index?

An Ankle-Brachial Index (ABI) is a simple and noninvasive test that measures the blood pressure in the ankles and arms to evaluate the presence of peripheral artery disease (PAD) or other vascular conditions. It is an essential diagnostic tool used by healthcare professionals to assess circulation in the lower extremities.

The ABI test compares the blood pressure in the ankle with the blood pressure in the arm. That comparison tells your provider a great deal about how well blood is flowing to your legs and feet.

• A lower ABI value can mean there is narrowing or blockage of the arteries in the legs.
• A higher ABI value may indicate the presence of non-compressible arteries, often seen in individuals with calcified or hardened arteries.

How Does an ABI Exam Work?

During an ABI exam, blood pressure measurements are taken at the ankles and arms using a blood pressure cuff and a Doppler ultrasound device. The procedure typically involves five steps:

1. Positioning — the person undergoing the test lies down in a supine position.
2. Cuff placement — blood pressure cuffs are placed on the arms and ankles.
3. Doppler measurement — the healthcare provider uses a Doppler ultrasound device to detect and amplify the sounds of blood flow in the arteries.
4. Inflation and deflation — the cuffs are inflated to temporarily stop blood flow and then gradually deflated to measure the systolic blood pressure at each location.
5. Calculation — the ratio of ankle pressure to arm pressure is calculated to determine the Ankle-Brachial Index.

ABI Interpretation and Ranges

Your ABI is calculated by dividing the higher of the ankle pressures by the higher of the arm pressures. This produces one of the following results:

Normal ABI (0.90 to 1.30)

Blood flow in the lower extremities is normal, and there is no significant artery obstruction or blockage.

Low ABI (Under 0.90)

This likely indicates the presence of peripheral artery disease (PAD), which means reduced blood flow to the legs and feet. The lower the ABI value, the more severe the blockage or narrowing of the arteries.

High ABI (Over 1.30)

This likely indicates the presence of non-compressible arteries, often seen in individuals with calcified or hardened arteries.

When Do I Need an ABI?

Your provider may recommend an ABI exam if you have PAD symptoms, such as leg pain when active. Your provider may also suggest this test (even if you do not have symptoms) if you fall into one of the following groups:

• Age 65 or older
• Age 50 to 64 and have certain risk factors for atherosclerosis, including diabetes, high blood pressure, high cholesterol, or a history of tobacco use, or a history of PAD in your biological family
• Under age 50 and have diabetes along with another risk factor for atherosclerosis

An ABI exam can catch PAD before it becomes severe. This gives you a chance to get treatment that may reduce your risk of serious complications, such as critical limb ischemia and amputation.

Who Should I Contact for Insurance Questions?

We highly recommend contacting your health insurance carrier to become familiar with your benefits and get a full list of coverage details for both wellness and problem-oriented visits. Additional tests required during a routine exam may not be covered under the routine exam benefit and could result in out-of-pocket expenses.

If you are uninsured or not using insurance, you are entitled to a Good Faith Estimate of the total expected cost of any items or services prior to scheduling your appointment.

For any additional questions about your Ankle-Brachial Index, please speak to our front desk staff.

Frequently Asked Questions About ABI Exams