Limb plethysmography is a test that is typically performed if a doctor suspects blockage or narrowing in your blood vessels. A different test, called an arteriography, is more accurate for this purpose. However, a limb plethysmography has several advantages over an arteriography.

A limb plethysmography can be done on patients who are too ill to travel to a lab. It also costs significantly less than an arteriography. Finally, it does not involve X-rays or contrast dye. This eliminates the risks of radiation exposure and allergic reactions to the dye. In fact, according to the National Institutes of Health (NIH), a limb plethysmography has no risks at all (NIH, 2012).

Avoid smoking for at least 30 minutes before the test.

You must remove all clothing from the arm and leg that will be tested. A doctor will instruct you to lie down while remaining partially propped up.

The doctor will put blood pressure cuffs around your arm and leg. He or she will then inflate these cuffs. Next, your doctor will measure the pulses from the cuffs.

By comparing the results, your doctor can tell whether there is a significant difference between the blood pressure in your arm and your leg.

The difference between the systolic blood pressure measurements in your arm and leg should be less than 20 mm Hg. An mm Hg is a unit of pressure.

Abnormal results may indicate any of the following:

  • arterial occlusive disease
  • blood clots
  • deep venous thrombosis
  • diabetes-related blood vessel changes
  • injury to an artery
  • vascular disease