Test for Venous Function

1. Make patient stand, apply a tourniquet at mid-thigh firmly enough to occlude the superficial veins, but not the deep veins or the arteries. 
2. Let the patient stand for 15 seconds and check for prompt venous filling before releasing tourniquet. If this occurs, deep veins are filling via incompetent perforating veins. . 
3. Release the tourniquet. If superficial veins fill promptly, valves are incompetent. If no prompt filling is noted, the valves are competent and veins are functioning, even though they appear dilated and tortuous.