A Doppler test on legs is a non-invasive test that uses ultrasound to look at the blood flow in the large arteries and veins in the legs. The test can help diagnose conditions such as peripheral vascular disease, blood clots, deep vein thrombosis, arterial occlusive disease, and venous insufficiency. During the exam, a water-soluble gel is placed on a handheld device called a transducer, which directs high-frequency sound waves to the artery or veins being tested. Blood pressure cuffs may be put around different parts of the leg, including the thigh, calf, and ankle. The test is not painful, but some people may feel slight pain from the pressure applied by the person performing the test. The exam is done in the ultrasound or radiology department, a hospital room, or in a peripheral vascular lab. The test is risk-free and pain-free, and it requires little preparation. If you show signs of decreased blood flow in the arteries or veins of your legs, arms, or neck, your doctor may suggest a Doppler ultrasound exam.