Foot circulation check (vascular assessment)

What is a foot circulation check?

A foot circulation check, or lower limb vascular assessment, is a set of checks of the blood supply to your legs and feet. Its main aim is to find peripheral arterial disease (PAD), where narrowed arteries reduce blood flow. It begins with your history and a physical examination, then usually moves to the ankle-brachial index (ABI), a test that compares blood pressure at your ankle with your arm¹². Podiatrists, nurses, doctors and surgeons all use the ABI³.

It matters because about 50% of people with diabetes and a foot ulcer also have PAD, which raises the risk of serious limb and heart problems⁴. PAD can also be painless in people with diabetes, because nerve damage can mask pain⁵.

Who needs a foot circulation check, and how often?

If you have diabetes, regularly. Everyone with a diabetes-related foot ulcer should have their circulation assessed, and an ulcer that hasn't healed within 4–6 weeks of good care needs further vascular investigation⁵. As part of routine foot checks, people at very low risk of ulcers are examined yearly. As risk rises, checks move to every 6–12 months, then every 3–6 months, then every 1–3 months⁶. Your podiatrist or GP can tell you which group you're in.

Bedside testing is also recommended if you are over 50, have artery disease elsewhere in your body, or are an Aboriginal or Torres Strait Islander person⁵.

If you don't have diabetes, a check is usually prompted by symptoms: leg pain on walking that eases within a few minutes of rest, numbness or weakness in the legs, or sores that won't heal. Smoking is the biggest risk factor⁷. Whether people with no symptoms should be screened isn't settled², so how often to recheck is a conversation to have with your GP or podiatrist.

What happens during the check?

First you'll be asked about leg pain when walking or at rest, wounds that are slow to heal, and risk factors such as smoking, diabetes, high blood pressure and high cholesterol⁸.

Next, your podiatrist or doctor looks at and feels your legs and feet. They check colour and temperature, pulses (in the groin, behind the knee, on top of the foot and inside the ankle), and skin changes such as hair loss, thickened or misshapen toenails and sores⁸⁹. They may also listen to blood flow with a stethoscope¹⁰. These signs are pointers only, because they can be caused by other things⁹.

Then comes the ABI. A blood pressure cuff and an ultrasound device are used on your ankle and arm, and it's painless¹⁰. If you have diabetes, a toe pressure test (the toe-brachial index) and a Doppler check of blood flow in the foot arteries are often added⁵. You may be asked to lie down, because checking a foot with the leg hanging down can falsely reassure⁹.

What do the results mean, and how accurate is it?

A normal ABI is roughly 0.9 to 1.3–1.4⁵⁹. Below 0.9 suggests reduced blood flow¹¹. Above about 1.4 is reported as non-compressible, meaning the arteries are too stiff to squeeze, and in people with diabetes, kidney disease or older age that reading is unreliable⁹⁸. A toe-brachial index below 0.7 is abnormal⁹. Services use slightly different cut-offs, so ask what yours mean.

What happens next depends on the result. A mildly low ABI (about 0.5–0.9) usually leads to a routine referral to a vascular service, and below 0.5 means an urgent referral⁸. With a diabetes-related foot ulcer, very low ankle or toe pressures prompt urgent vascular imaging⁵.

The ABI is better at confirming PAD than ruling it out. A low result is a reliable sign, but a normal one can miss disease, especially in older people, people with diabetes and when arteries are calcified¹²¹¹. Normal results are best read alongside your pulses, skin findings and how a wound is healing¹¹.

What are the limits, and what are the alternatives?

No single test can reliably rule PAD out. For people with diabetes, guidelines advise combining the ABI with toe pressure or Doppler checks of the foot arteries⁵. The toe test is less likely to be thrown off by stiff arteries, but there is less research behind it¹³. The ABI can read falsely normal in people with diabetes or kidney disease for the same reason⁹. Pulse and skin checks alone aren't enough either⁹.

If an ulcer isn't healing even though tests look normal, further vascular investigation such as imaging should follow⁵.