Introducing some non-invasive tests that can easily and accurately determine the degree of limb ischemia When the limb appears cold and numb or even painful, we should be careful if the artery is blocked, and it is time to go to the hospital in time, especially for diabetic patients, and we should not take it lightly. The most accurate test to determine whether the limb is ischemic and the degree of ischemia is of course arteriography, but it is an invasive test, and the cost is also high. Ultrasound can reflect the image of a small section of blood vessel directly on the screen, which can determine whether there is plaque in the wall of blood vessel, whether there is thrombus in the lumen, whether there is stenosis, whether the blood flow is smooth, and can also help determine the degree of obstruction of blood vessel by tracing the waveform of blood flow, based on the waveform pattern and blood flow rate. [Doppler arterial function test] is also done by using the reflection of the Doppler probe, and the price is similar to that of ultrasound. Currently, limb segmental manometry and toe end microcirculation measurement can be done with a circumferential vascular examiner. First, it detects the blood flow in various parts of the limb by ultrasound probes and traces it as a waveform, by which the physician can generate a preliminary understanding of the local vascular blood flow velocity and vascular elasticity. Then, by inflating each segment of the upper and lower extremities, the pressure is measured segment by segment. The pressure measurement can yield two extremely valuable results: the first is the ratio of the upper extremity pressure (brachial artery) to the pressure of each segment of the lower extremity, which can reflect whether the lower extremity is ischemic and the location and degree of the ischemic lesion; the second is the pressure gradient between each segment of the lower extremity, and if the two adjacent parts (such as thigh-superior knee, superior knee-suberior knee, inferior knee-ankle, etc.) If the pressure gradient is too large and exceeds 30 mmHg, especially if it exceeds 50 mmHg, it clearly indicates that the segment has stenosis or even occlusion of large blood vessels, and reminds patients that they should go to the hospital for systematic treatment as soon as possible to prevent the development of foot ischemia to ulceration, infection or even necrosis, and to reduce the amputation rate of diabetic foot. In addition, the ankle pressure measurement, vascular waveform and toe microcirculation examination can also be used to determine microvascular lesions, which is very important for diabetic patients.