Ankle Brachial Index

Ankle Brachial Index

The Ankle-Brachial Index (ABI) is a simple and non-invasive test that measures the blood pressure in the ankles and arms to evaluate the presence of peripheral artery disease (PAD) or other vascular conditions. It is an essential diagnostic tool used by healthcare professionals to assess the circulation in the lower extremities. Here’s how the ABI works and why it is important:


During an ABI test, blood pressure measurements are taken at the ankles and arms using a blood pressure cuff and a Doppler ultrasound device.

The procedure typically involves the following steps:
  • The person undergoing the test lies down in a supine position.
  • Blood pressure cuffs are placed on the arms and ankles.
  • The healthcare provider uses a Doppler ultrasound device to detect and amplify the sounds of blood flow in the arteries.
  • The cuffs are inflated to temporarily stop blood flow, and then gradually deflated to measure the systolic blood pressure at each location.
  • The ratio of ankle pressure to arm pressure is calculated to determine the Ankle-Brachial Index.
  • The ABI is calculated by dividing the higher of the ankle pressures by the higher of the arm pressures. Here’s how the ABI results are interpreted:
Normal ABI (0.90-1.30): A normal range indicates that blood flow in the lower extremities is normal, and there is no significant obstruction or blockage in the arteries.
ABI < 0.90: A lower ABI value suggests the presence of peripheral artery disease (PAD), which indicates reduced blood flow to the legs and feet. The lower the ABI value, the more severe the blockage or narrowing of the arteries.
ABI > 1.30: A higher ABI value may indicate the presence of non-compressible arteries, often seen in individuals with calcified or hardened arteries.


Importance of ABI Testing: The ABI test is an important diagnostic tool for several reasons:

Early Detection of Peripheral Artery Disease (PAD):

ABI testing helps identify PAD at an early stage, allowing for timely intervention and management. Early detection and treatment can prevent the progression of PAD, reduce symptoms, and lower the risk of complications such as non-healing wounds or amputation.

Assessing Cardiovascular Risk:

PAD is often associated with an increased risk of cardiovascular events such as heart attack or stroke. ABI testing helps identify individuals who may be at a higher risk for these events, allowing for appropriate interventions and preventive measures.

Monitoring Treatment Effectiveness:

For individuals diagnosed with PAD, ABI testing can be used to monitor the effectiveness of treatment and track changes in blood flow over time. Regular ABI measurements help healthcare providers assess the response to interventions such as lifestyle modifications, medication, or surgical procedures.

Screening in High-Risk Populations:

ABI testing is recommended for individuals who are at a higher risk of developing PAD, such as those with diabetes, a history of smoking, hypertension, or high cholesterol. It is a valuable screening tool to identify early signs of peripheral artery disease in these populations.

Remember, ABI testing should be conducted by a qualified healthcare professional, such as a vascular specialist or a cardiologist, to ensure accurate results and appropriate interpretation. If you have concerns about your leg circulation or risk factors for peripheral artery disease, consult with your healthcare provider to determine if ABI testing is necessary.