Lung diffusion testing is used to determine how well oxygen passes from the air sacs of the lungs into the blood. The test measures the “diffusing capacity of the lung for carbon monoxide” or DLCO. The other name of diffusion test is Diffusing capacity; DLCO test.
You breathe in (inhale) some gas containing a very small quantity of carbon monoxide, hold your breath for 10 seconds, and then rapidly blow it out (exhale). The single exhaled gas is analyzed to determine how much carbon monoxide was absorbed during the breath. Do not eat a heavy meal before the test. Do not smoke for at least 4 – 6 hours prior to the test. If you use a bronchodilator or inhaler medications, ask your health care provider whether or not you can use them before the test.
The test is used to diagnose the presence and extent of certain lung diseases like ILD (Interstitial Lung disease). It may also be used to see how gases move from the lungs into the bloodstream.
Normal test results depend on a person’s age, sex, height & Hemoglobin.