Diffusing Capacity Test

The Diffusing Capacity Test measures how effectively gases, like oxygen, pass from your lungs into your blood. During the test, a person breathes in a harmless gas mixture, holds their breath briefly, then exhales. The test determines how much of the gas moves into the blood, which helps assess lung health, especially the alveoli—the tiny air sacs where oxygen transfer occurs. It is useful for diagnosing and monitoring lung conditions such as emphysema, fibrosis, or other lung diseases affecting gas exchange efficiency.