Ankle-Brachial Index

A test for peripheral vascular disease in which blood pressure readings of the arms are compared with readings of the ankles.

People with diabetes, especially Type 2 diabetes, are at increased risk for peripheral vascular disease, in which fatty deposits thicken and clog arteries in the legs. This can lead to intermittent claudication, which is painful cramping and fatigue in the legs while walking. Peripheral vascular disease can also make it difficult for foot injuries to heal and compromise the body’s ability to fight infections, which – in combination with diabetic neuropathy (nerve disease) – can set the stage for a foot ulcer.


The ankle—brachial index (ABI) is used to screen for peripheral vascular disease. The test takes about 20–30 minutes. First, the person lies down for about 10 minutes to equalize the effect of gravity on blood pressure in the arms and legs. Then a blood-pressure cuff and/or a Doppler probe, which uses sound waves to detect blood flow, is used to measure blood pressure in the arms and at the ankles. If systolic blood pressure at the ankles is lower than in the arms, this may indicate the presence of peripheral vascular disease.

Severe peripheral vascular disease is sometimes treated with surgery to bypass the blocked blood vessel or using endovascular techniques (which widen blood vessels from the inside). There are many ways to help prevent peripheral vascular disease, including controlling blood glucose levels, following a diet low in saturated fat and cholesterol, not smoking, taking a blood-thinning drug such as aspirin (under a doctor’s supervision), and taking regular walks to promote circulation in the legs and feet.