Limb plethysmography is a test that compares blood pressure in the legs and arms.
This test may be done in the health care provider's office or in a hospital. You will be asked to lie with the upper part of your body slightly raised.
Three or four blood pressure cuffs are wrapped snugly around your arm and leg. The provider inflates the cuffs, and a machine called a plethysmograph measures the pulses from each cuff. The test records the maximum pressure produced when the heart contracts (systolic blood pressure).
Differences between the pulses are noted. If there is a decrease in the pulse between the arm and leg, it may indicate a blockage.
When the test is complete, the blood pressure cuffs are removed.
Do not smoke for at least 30 minutes before the test. You will be asked to remove all clothing from the arm and leg being tested.
You should not have much discomfort with this test. You should only feel the pressure of the blood pressure cuff. The test often takes less than 20 to 30 minutes to perform.
This test is most often done to check for narrowing or blockages of blood vessels (arteries) in the arms or legs.
There should be less than a 20 to 30 mm Hg difference in the systolic blood pressure of the leg compared with that of the arm.
Abnormal results may be due to:
Other conditions for which the test may be performed:
If you have an abnormal result, you may need to have more testing to find the exact site of the narrowing.
There are no risks.
This test is not as accurate as an arteriography. Plethysmography may be done for very ill people who cannot travel to the arteriography lab. This test can be used to screen for vascular disease or to follow up earlier abnormal tests.
The test is noninvasive, and it does not use x-rays or injection of dye. It is also less expensive than an angiogram.
Reviewed By: Deepak Sudheendra, MD, FSIR, RPVI, Assistant Professor of Interventional Radiology & Surgery at the University of Pennsylvania Perelman School of Medicine, with an expertise in Vascular Interventional Radiology & Surgical Critical Care, Philadelphia, PA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.