What Is an Ankle-Brachial Index Test?
An ankle-brachial index (ABI) test is a simple way for your doctor to check how well your blood is flowing. They use this test to check for peripheral artery disease (PAD). When you have this condition, it means you have blockages in the arteries of your arms and legs. This slows your blood flow, so your limbs don’t get all the oxygen they need.
If you have PAD, you’re more likely to have a stroke or heart attack. The ABI test compares the blood pressure at your ankle with the blood pressure at your arm. If you have a low score on this test, you probably have poor blood flow in your legs.
Why the Ankle-Brachial Index Test Is Done
You might need the ankle-brachial index test for a few reasons:
- Your chances of PAD are higher than normal.
- You’re more likely to get PAD as you get older. Even if you don’t have any symptoms, you may want to get the test if you’re 70 or older.
You’re also more likely to have this kind of blood flow problem if you’re 50 or older and you have any of these:
- A history of smoking
- High blood pressure
- High cholesterol
Ankle-Brachial Test Procedure
The test lasts 10 to 15 minutes. First, you lie down on a table. Your doctor wraps a cuff around your arm to take your blood pressure. You’ll feel mild pressure while it inflates, but that doesn’t last long.
Your doctor will use a Doppler ultrasound device, a plastic tool that’s a little smaller than a computer mouse. It connects to a speaker so they can hear your blood flow.
To use the device, your doctor will first put a dab of gel on your arm just below the blood pressure cuff. Then, they’ll put the ultrasound device on the gel. This helps them know when to take your blood pressure reading.
They’ll do the same steps on your other arm and then on both ankles.
If you have leg pain and your doctor wants to make sure it’s PAD, you might take an exercise ankle-brachial index test. For this, you’ll have two ankle-brachial index readings: one before and one after walking on a treadmill.