Diffusing Capacity (DLCO)

The DLCO tests the ability of air to cross through your lungs and into your blood stream without actually drawing any blood. After taking a deep breath of normal air mixed with a tiny bit of harmless but rare gas, you are asked to hold your breath for ten seconds. After you exhale, this test determines how much of the rare gas passed into your blood, indicating how well oxygen gets in and carbon dioxide gets out. The DLCO test is very helpful in differentiating emphysema from other obstructive diseases.