Residual Volume (RV)
Residual volume is the amount of air that remains in a person's lungs after fully exhaling. Doctors use tests to measure a person's residual air volume to help check how well the lungs are functioning.
Residual volume is measured by:
- A gas dilution test. A person breathes from a container containing a documented amount of a gas (either 100% oxygen or a certain amount of helium in air). The test measures how the concentration of the gases in the container changes.
- Body plethysmography. This test measures the total amount of air the lungs can hold (total lung volume). For this test, a person sits inside an airtight booth called a plethysmograph and breathes through a mouthpiece while pressure and air flow measurements are collected.
|Primary Medical Reviewer||E. Gregory Thompson, MD - Internal Medicine|
|Specialist Medical Reviewer||Mark A. Rasmus, MD - Pulmonology, Critical Care Medicine, Sleep Medicine|
|Last Revised||April 25, 2013|