Non-Invasive Testing Methods For PAD Whenever one suspects Peripheral Arterial Disease (PAD), the clinician must perform few non-invasive vascular testing methods that are commercially available and widely implemented. They include the ankle brachial index ABI), the toe-brachial index(TBI), segmental Pressure Study and pulse volume recording(PVR) and transcutaneous oxygen monitoring(TCPO2). Ankle Brachial Index: The ankle brachial index is the most well-known, non-invasive vascular testing tool. ABI test is performed with a Doppler and a blood pressure cuff. One calculates the ABI by dividing the ankle pressure by the brachial systolic pressure. An ABI of < 0.9 is abnormal and ABI values have a linear correlation with wound healing potential in lower extremity wounds. Patients with DM may have calcified and hardened lower extremity arterial walls that cannot be readily compressed and occluded with blood pressure cuffs. This produces falsely elevated ankle pressure readings that are often in the “normal ABI range” (0.9 to 1.4) or sometimes in the non-physiological range of above 1.4. However, Calcified leg arteries in Diabetes Mellitus or dialysis patients may yield falsely elevated ABI results. Toe-Brachial Index: The digital arteries in great toes are less affected by medial arterial calcification. One would calculate TBI by dividing the blood pressure of the great toe by the systolic brachial blood pressure. A TBI value of < 0.7 is considered abnormal. Absolute Toe pressure of > 55mmHg is considered normal. Toe pressure < 30 mmHg is considered severely ischemic.