Ankle Brachial Index (ABI)

Image of a blood pressure measurement of an ankle artery.The Ankle/Brachial Index (ABI) is a test that detects arterial disease in the legs by calculating a ratio from the blood pressure in the arms and the blood pressure at the ankles. 

Arterial waveforms and blood pressure measurements are acquired using a hand held Doppler probe applied to the arms and ankles.

Why is an ABI performed?

This test is used to:

  • Determine the presence or absence of peripheral arterial disease in the legs.
  • Monitor existing arterial disease, or follow-up after surgical intervention.

Can I eat or drink on the day of the test?

Yes. Eat and drink as you normally would the day of the test (unless you are also scheduled that day for an ultrasound exam that requires fasting).

Should I take my medications the day of the test?

Take all of your medications at the usual times, as prescribed by your doctor.

What happens during the test?

  • A vascular sonographer will perform the test.
  • The sonographer will ask you to remove your socks and shoes and to lie on your back on an exam table. Blood pressure cuffs will be placed around your ankles.  The sonographer will obtain blood pressure measurements at both ankles and also on both arms. 
  • Depending on the type of ABI test requested by your physician, you may be asked to walk on a treadmill for 5 minutes or do another modified exercise.  Blood pressure measurements will be retaken immediately after exercise. 
  • In some circumstances, the sonographer may also take blood pressure measurements on your toes.

How will I feel during the test?

You may feel fatigue or leg pain during the exercise portion of this test.  

How long does the test take?

This exam usually takes about 30 minutes, depending on many variables. After the test, you may go home or go to your other scheduled appointments.

How do I get the results of my test?

After a vascular surgeon has interpreted your exam, the results will be sent to your referring physician and/or the vascular surgeon will go over the results with you during a follow-up appointment.