Venous Doppler studies use a technique called Doppler ultrasound to evaluate blood circulation in the veins of the arms or legs. A device called a transducer is passed lightly across different areas of your limbs, directing high-frequency sound waves (ultrasound) at superficial and deep veins. The sound waves are reflected back at frequencies that correspond to the velocity of blood flow, and are converted into audible sounds and graphic recordings.

Duplex scanning combines Doppler ultrasound with real-time ultrasound imaging of the veins. Images are displayed on a viewing monitor and may also be recorded on film or video for later examination.

Purpose of the Venous Duplex Ultrasound

  • To evaluate venous blood flow in the arms and legs in people with symptoms such as leg pain and swelling, swollen arms and legs, or varicose veins in the arms or legs.
  • To aid in the diagnosis of venous abnormalities such as a suspected blood clot in a deep vein of the leg (deep vein thrombosis); narrowing or closure (occlusion) of a vein; or impaired blood flow (venous insufficiency).

Who Performs Venous Duplex Ultrasound

  • A qualified vascular laboratory technician.

Special Concerns about Venous Duplex Ultrasound

  • This test is often unable to detect blood clots in a calf vein. Venous plethysmography and venography are more accurate for this purpose.

Before the Venous Duplex Ultrasound

  • Tell your doctor about any medications you are taking, especially blood pressure medications or blood thinners.
  • You will be asked to remove any clothes covering the area to be examined and put on a hospital gown.

What You Experience During Venous Duplex Ultrasound

  • You will lie on either a bed or a table.
  • A small amount of water-soluble gel is applied to the skin on the areas being examined to enhance sound wave transmission.
  • The examiner then moves the transducer back and forth over the selected limb to record blood flow and obtain different views of the vein or veins being studied. You will be instructed to breathe normally as this is done.
  • Once clear images are obtained, they are recorded on film or video for later analysis.
  • Additional images will be obtained after the examiner applies brief pressure to compress and release certain veins, and as you perform certain breathing exercises to vary blood flow through the veins.
  • The test usually takes 20 to 30 minutes.

Risks and Complications of Venous Duplex Ultrasound

  • Ultrasound is painless, noninvasive, and involves no exposure to radiation. There are no associated risks.

After the Venous Duplex Ultrasound

  • The examiner removes the conductive gel from your skin.
  • You may resume your normal activities.

Results of Venous Duplex Ultrasound

  • A physician reviews the images and other test data for evidence of any abnormality.
  • If a definitive diagnosis can be made, appropriate treatment will be initiated.
  • In some cases, additional tests, such as venography, are required to further evaluate abnormal findings.


The Johns Hopkins Consumer Guide to Medical Tests

Simeon Margolis, M.D., Ph.D., Medical Editor

Updated by Remedy Health Media

Publication Review By: the Editorial Staff at

Published: 25 Jan 2012

Last Modified: 13 Jan 2015