Venous reflux testing with ultrasound is a non-invasive, outpatient test that utilizes high frequency sound waves to obtain images of veins in the arms or legs and evaluate for reflux. This test is used to identify the presence and duration of venous blood flow reversal or reflux in the extremities. It is done when there is suspected chronic venous disease, pain, swelling, pigmentation changes, or ulceration of the lower extremity. This test is used to determine if there are problems with the vessels which may result in varicose veins, pain, and swelling. The sonographer applies an acoustic gel to your extremities being tested. A painless instrument called a transducer is gently moved across that portion of your body to visualize the inside of the veins. A physician interprets the results of this test and makes recommendations.