• A venogram is an x ray of a vein. The test uses a contrast agent (dye) that is injected to make veins visible on x ray.
    This test is used to look for blood clots in the deep veins of the legs or arms (deep vein thrombosis) and to show images of veins that are being evaluated for treatment of chronic venous insufficiency.
  • Although it is usually safe, venography is an invasive test. Possible complications include clot formation, allergic reaction, and kidney problems.
  • A venogram is an x ray that allows the physician to see the anatomy of a vein. During this test, a physician injects an iodine-containing contrast dye, most often in a small vein on the top of the foot. This dye is radiopaque, meaning that it makes blood vessels appear on an x ray. The test is usually performed on an outpatient basis.
  • Venography is an invasive test that has potential complications. Therefore, it is usually used when the results from noninvasive testing are conflicting or when the treating physician needs to see the inside of the vein for evaluation of structures in it, such as valves.
  • Venography can also guide vascular specialists during minimally invasive treatments for diseased veins.


No special preparation is usually needed for a venogram.

Before the test, the physician will advise that the patient drink plenty of liquids to ensure that he or she is hydrated, which reduces the risk for kidney complications from the contrast material.

The patient should notify the physician if he or she has an allergy to iodinated contrast material. Pregnant women should discuss with their physician whether venography is appropriate, because x rays may harm the fetus.


The following factors increase the risk for kidney failure, a possible complication of the venogram:

  • Advanced age
  • Diabetes mellitus
  • Multiple myeloma (a type of blood cancer)
  • Dehydration
  • Poor kidney function

Very rarely, the injection of the dye has dislodged blood clots or caused clots to form in the veins that were injected. Other risks come from the contrast material, and include allergic reactions and kidney problems.


Before any punctures are made, the part of the body to be accessed is shaved, cleaned, and surrounded with a sterile drape. If requested, the physician applies a local anesthetic.

The physician then inserts a needle or catheter into a vein in the vein and injects the contrast agent. The patient may feel a brief warm flushing sensation during this part of the procedure, which accounts for most of the discomfort involved in the test. X rays are taken as the dye flows through the veins being studied. The patient is asked to lie perfectly still to prevent sudden movements from distorting the x ray pictures.

After the x rays have been taken, the catheter is removed and manual pressure is applied to the area for 10 to 20 minutes to stop any bleeding.The test generally takes between 30 and 90 minutes.


After the procedure, the patient is observed for several hours for any signs of complications such as bleeding from the injection site, infection, or an allergic reaction. Fluids are given to clear the contrast agent from the patient’s body and to prevent dehydration.

A venogram requires interpretation by a physician.

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Medical Review Date: August 14, 2003 / Copyright © 2012 NorthPoint Domain, Inc. All rights reserved. This material cannot be reproduced in digital or printed form without the express consent of NorthPoint Domain, Inc. Unauthorized copying or distribution of NorthPoint Domain’s Content is an infringement of the copyright holder’s rights.