Ankle brachial index test

Overview

The ankle-brachial index (ABI) test is a simple, painless test that checks for reduced blood flow to your legs. It compares the blood pressure in your ankle with the blood pressure in your arm. A lower reading in your ankle can be a sign of narrowing or blockage in the arteries of your legs, a condition called peripheral artery disease (PAD).

Doctors often perform the ABI test when they suspect someone has poor circulation in their legs. It is a routine, non-invasive test done in clinics and hospitals.

The ABI test is most often used for people who have risk factors for peripheral artery disease, such as smokers, people with diabetes, high blood pressure, high cholesterol, or those over age 50. It can also be used for anyone with leg pain while walking.

Symptoms

Common symptoms

• Leg pain or cramping when walking that goes away with rest (called claudication)
• Numbness or weakness in the legs
• Coldness in the lower leg or foot compared to the other leg
• Sores on the toes, feet, or legs that heal slowly or not at all
• Change in the colour of the legs (pale or bluish)
• Hair loss or slower hair growth on the legs

Symptoms in children

• This test is rarely used in children, but if a child has symptoms like leg pain or delayed healing, a doctor may order it to check for rare blood vessel problems.

Symptoms in older adults

• The same symptoms apply, but older adults may also notice fatigue or heaviness in the legs during activity without actual pain.

Causes

Main causes

• Atherosclerosis – a buildup of fatty plaques inside the arteries that narrows them and reduces blood flow.

Risk factors

• Smoking or using tobacco
• Diabetes
• High blood pressure
• High cholesterol
• Age over 50
• Obesity
• Lack of physical activity
• Family history of heart disease or peripheral artery disease

When to see a doctor

See a doctor urgently if:

• Any sudden, severe leg pain or change in skin colour (pale, blue, cold)
• A leg wound that is not healing or shows signs of infection (redness, swelling, pus)

Book a routine appointment if:

• Leg pain or cramping when walking that goes away with rest
• Numbness or coldness in one leg compared to the other
• Unexplained sores on your feet or legs
• If you have risk factors and want to check your circulation

Diagnosis

Your doctor will ask about your symptoms, medical history, and risk factors. If they suspect peripheral artery disease, they will recommend an ABI test. The test is usually done in a doctor’s office or a vascular lab.

Tests that may be done

• Ankle-brachial index (ABI) test: Blood pressure cuffs are placed on your arms and ankles. Your doctor takes blood pressure readings at both sites, then calculates a ratio. A ratio below a certain number suggests PAD.
• Doppler ultrasound: Sometimes combined with the ABI to listen to blood flow in the arteries.
• Exercise ABI test: If your resting ABI is normal but you have symptoms, the test may be repeated after walking on a treadmill.

What to expect at your appointment

You will lie down for about 10 minutes before the test. A cuff is placed on your upper arm and another around your ankle. The cuffs are inflated and then slowly deflated while a special device records the blood pressures. The test is painless and takes about 15 to 20 minutes.

Treatment

Treatment for peripheral artery disease focuses on managing risk factors and improving blood flow. It often includes lifestyle changes and, if needed, medicines or procedures. Your doctor will work with you to create a plan based on your symptoms and test results.

Self-care at home

• Quit smoking – this is the single most important step you can take.
• Walk regularly – a supervised walking programme can help reduce pain and improve circulation.
• Keep your blood pressure, blood sugar, and cholesterol under control with diet and exercise.
• Take care of your feet – check them daily for cuts or sores, and wear comfortable shoes.

Medical treatments

Your doctor may recommend medicines to help lower blood pressure, reduce cholesterol, prevent blood clots, or control blood sugar. Some medicines can help improve walking distance. Always take your medicines exactly as prescribed.

When is surgery considered?

If symptoms are severe or a blockage is critical, your doctor may suggest a procedure such as angioplasty (opening the artery with a balloon) or bypass surgery (using a graft to reroute blood flow). These are only considered when lifestyle and medicines aren’t enough.

Living with this condition

Living with peripheral artery disease means taking good care of your health. Stay active within your limits, wear comfortable shoes, and check your feet daily for any problems. Let your doctor know if symptoms change.

Lifestyle tips

• Stop smoking
• Stay physically active – aim for at least 30 minutes of walking most days
• Eat a heart-healthy diet low in salt, saturated fat, and added sugars
• Maintain a healthy weight
• Manage stress
• Limit alcohol

Diet and exercise

Eating plenty of fruits, vegetables, whole grains, and lean proteins can help control blood pressure and cholesterol. A walking programme, even if you have pain, can gradually improve your walking distance. Your doctor or a physiotherapist can guide you.

Mental health and emotional wellbeing

Living with a chronic condition like PAD can sometimes feel frustrating or worrying. It is normal to have concerns. Talking to your doctor, joining a support group, or speaking with a counsellor can help.

Prevention

You cannot always prevent peripheral artery disease, but you can lower your risk by avoiding smoking, staying active, eating well, and keeping blood pressure, cholesterol, and diabetes under control. These steps also help slow the progression if you already have PAD.

Screening programmes

Screening with the ABI test is not recommended for everyone. Your doctor may suggest it if you have risk factors or symptoms. Talk to your doctor if you think you should be tested.

Complications

If left untreated

• Progressive leg pain that limits walking and daily activities
• Non-healing sores or ulcers that can become infected
• Gangrene (tissue death) that may lead to amputation
• Increased risk of heart attack or stroke

Long-term outlook

With early diagnosis and proper management, most people with peripheral artery disease can maintain a good quality of life. Many people find that walking and lifestyle changes greatly improve their symptoms. Your healthcare team will help you take steps to protect your health and prevent complications.

Find support

External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.