The ABI is an easy to perform non-invasive test which compares the highest systolic brachial pressure to the highest ankle pressure by dividing the ankle pressure by the brachial pressure.
A Toe Brachial Index or TBI is performed when the ABI or Ankle Brachial Index is abnormally high due to plaque and calcification of the arteries in the leg; this is caused by atherosclerosis and is most often found in diabetic patients. The abnormally high ABI is >1.3.
