The ankle-brachial pressure index (ABPI) or ankle-brachial index (ABI) is the ratio of the blood pressure at the ankle to the blood pressure in the upper arm (brachium). Compared to the arm, lower blood pressure in the leg suggests blocked arteries due to peripheral artery disease (PAD). The ABPI is calculated by dividing the systolic blood pressure at the ankle by the systolic blood pressure in the arm

Use a Doppler Probe to measure Ankle-Brachial Pressure Index. Measure systolic BP in both arms. Measure systolic BP in posterior tibial arteries and dorsal pedis of one leg. Divide the highest ankle pressure by highest brachial pressure to calculate ABPI.