An ankle-brachial index (ABI) test is one of the most common tests used to diagnose peripheral vascular disease (PVD). An ABI test compares the blood pressure in your ankle and your arm. Here’s what happens during an ABI test:
- Getting ready. You’ll change into a gown and lie down on an exam table.
- Blood pressure cuffs. A technician will place blood pressure cuffs on your arms and ankles and inflate the cuffs.
- Ultrasound. As the cuffs deflate, a technician will hold an ultrasound device called a transducer against each ankle and arm. The device uses high-frequency sound waves to measure the blood pressure in each area.
- Ratio. The ankle blood pressures will be divided by the highest arm pressure to create an ABI ratio. A ratio lower than normal means you probably have peripheral arterial disease (PAD).
- Treadmill exercise, then a second measurement (optional). Depending on your situation, you might exercise on a treadmill. You will then have another ABI test. Note: If you don’t feel well during the test, ask the technician to stop the treadmill. Wait for the treadmill to stop completely before you step off it.