What is Ankle-Brachial Index?
The ankle-brachial index test is a quick, noninvasive way to check for peripheral artery disease (PAD). The disease occurs when narrowed arteries reduce the blood flow to your limbs. PAD can cause leg pain when walking and increases the risk of heart attack and stroke.
The ankle-brachial index test compares the blood pressure measured at your ankle with the blood pressure measured at your arm. A low ankle-brachial index number can indicate narrowing or blockage of the arteries in your legs.
You may have ankle-brachial index testing before and immediately after walking on a treadmill. An exercise ankle-brachial index test can assess the severity of the narrowed arteries during walking.
Why is Ankle-Brachial Index performed?
The ankle-brachial index test is done to check for PAD — narrowed arteries that reduce blood flow, usually in your legs. Research indicates that PAD affects about 10 percent of people over age 55.
Your doctor might recommend an ankle-brachial index test if you have leg pain while walking or risk factors for PAD, such as:
What should I know before receiving Ankle-Brachial Index?
Ankle-Brachial Index may be contraindicated in:
- Patients who are unable to remain supine for the exam
- Patients in whom the occlusion from the blood pressure cuff may worsen the extremity injury
You may feel some discomfort when the blood pressure cuffs inflate on your arm and ankle. But this discomfort is temporary and should stop when the air is released from the cuff.
If you have severe leg pain, your doctor may recommend a different imaging test of the arteries in your legs.
How to prepare for Ankle-Brachial Index?
Generally, you won’t need to follow any special instructions before your appointment to have an ankle-brachial index test performed. You may want to wear loose, comfortable clothing that allows the technician performing your ankle-brachial index test to easily place a blood pressure cuff on your ankle and upper arm.
What happens during Ankle-Brachial Index?
You likely will be asked to rest for 5 to 30 minutes before the test.
Typically, you lie on a table on your back, and a technician measures your blood pressure in both arms and both ankles, using an inflatable cuff and a hand-held ultrasound device that’s pressed on your skin. The device uses sound waves to produce images and allows your pulse to be heard in your ankle arteries after the cuff is deflated.
What happens after Ankle-Brachial Index?
The ankle-brachial index test should take only a few minutes. You don’t need to follow any special precautions afterward. Your doctor will discuss your test result with you.
If you have any questions about the Ankle-Brachial Index, please consult with your doctor to better understand your instructions.
Explanation of results
What do my results mean?
Your doctor uses the blood pressure results to come up with a number called the ankle-brachial index. Here’s what the numbers mean:
- 9 or less. You have PAD. The lower the number, the more blockage you have.
- 0-1.4. You don’t have PAD.
- Over 1.4. The test isn’t helpful to you. This result means you have stiff arteries, and you can’t get useful blood pressure numbers with the cuff. Your doctor will turn to a different test.
If you took an exercise ankle-brachial index test, the range of results may be a little different. Your doctor will look at your results, symptoms, and health history to help you decide what comes next.
You may need changes to your lifestyle or to start taking medicine. In some cases, your doctor may suggest surgery.
If you have severe PAD, your doctor may send you to a vascular specialist, a doctor who treats diseases in arteries and veins.
Depending on the laboratory and hospital, the normal range for Ankle-Brachial Index may vary. Please discuss with your doctor any questions you may have about your test results.
Hello Health Group does not provide medical advice, diagnosis or treatment.
What Is an Ankle-Brachial Index Test? https://www.webmd.com/heart-disease/ankle-brachial-test. Accessed October 9, 2018.
Physical Examination: Ankle Brachial Index (ABI). https://www.ebmconsult.com/articles/physical-exam-ankle-brachial-index-abi. Accessed October 9, 2018.
Ankle-brachial index. https://www.mayoclinic.org/tests-procedures/ankle-brachial-index/about/pac-20392934. Accessed October 9, 2018.
Review Date: November 4, 2018 | Last Modified: November 4, 2018