The ABI: What you should know

Were you recently screened for peripheral arterial disease (PAD) or peripheral vascular disease (PVD)? Thousands of Americans participated recently in Legs For Life™, a nationwide, screening program. Perhaps you participated and received a free screening but are curious to learn more about the test and what the results mean.

What test was it? You probably received the ankle-brachial index (ABI) exam, a simple and reliable method for diagnosing peripheral arterial disease (PAD). Blood pressure measurements are taken at the arms and ankles using a pencil shaped ultrasound device called a Doppler. A Doppler instrument produces sound waves (not x-rays) and is considered noninvasive because it does not require the use of needles or catheters. The ABI is one of the tests most widely used as a first step in diagnosing PAD.

What happened during the exam? While lying on your back, cuffs were placed on your ankles and arms. These cuffs were inflated briefly above your normal systolic blood pressure. Once the cuffs were deflated, blood pressure measurements were recorded. Then the ankle systolic pressures were divided by the highest arm pressure to establish an ABI measurement for each leg.

What do the measurements mean? The number that the doctor or technician came up with will probably be between .4 and 1.2 and these numbers are typically interpreted as:

.95 – 1.2 *		Normal
.94 or lower		Results are not normal

(*A measurement greater than 1.2 is not considered reliable, and other tests would need to be performed depending on symptoms and risk factors.)

What should happen after the exam? If your ABI indicated results that are outside of the normal index, you should make an appointment to discuss the results with your physician. Be sure to take the results with you. For more information on the ABI, visit our web site (www.vdf.org) and click our button for Peripheral Arterial Disease. You'll find the information listed under "Diagnosis."