ABI value indicating abnormal?

• A. <0.95 abnormal
• B. >0.96 normal
• C. <0.80 probable claudication
• D. <0.30 ischemic rest pain

Answer: (A)

Ankle-brachial index measures leg perfusion by comparing the ankle systolic pressure to the brachial systolic pressure. A normal ABI is about 1.0, so values that fall below a typical cutoff indicate abnormal perfusion due to arterial narrowing. In many exam contexts, that cutoff is 0.95, so an ABI below 0.95 signals abnormal perfusion from peripheral arterial disease. The lower the value, the more severe the obstruction tends to be: below around 0.80 often correlates with claudication, and very low values (roughly 0.30 or less) can indicate ischemic rest pain. An ABI above about 0.96 is generally considered normal. Therefore, a value under 0.95 is the best indicator of abnormal perfusion in this question.