About… the Ankle-Brachial Index (ABI)

The ankle-brachial index (ABI) is a simple and reliable means for diagnosing PAD. Blood pressure measurements are taken at the arms and ankles using a pencil-shaped ultrasound device called a Doppler (an instrument that produces sound waves, not x-rays) or other specialized measuring instrument. These are considered non-invasive because they do not require the use of needles or catheters. The ABI test is simple enough to be performed in any doctor's office or vascular laboratory. Not only is the ABI one of the most reliable tests for PAD, it is also the least expensive.

The ABI exam can be used to assess whether PAD is getting worse and to establish the severity of an individual's atherosclerosis (build-up of plaque) as well as to ascertain the risk of leg problems, such as development of leg-rest pain, poor healing of foot wounds, the need for bypass surgery, or amputation. It can also predict the risk of future problems from atherosclerosis such as heart attack and stroke.

For the exam, you will be asked to lie on your back while standard blood pressure cuffs are placed around your ankles and arms. Blood pressure measurements are taken and recorded, and a ratio is calculated for each leg. The ABI range that is generally considered normal is .95 to 1.3.

The ABI is extremely reliable, but may not be accurate in all patients. Some patients with long-standing diabetes, kidney disease, and some elderly patients may have stiff blood vessels. In these patients the ABI reading may be falsely elevated, thus additional testing is needed.

For more information or to receive a free copy of VDF's new "Focus on the ABI" educational pamphlet, please contact us at 888.VDF.4INFO (888.833.4463) or you may download a copy online at www.vdf.org.