DLCO Test (Diffusing Capacity of the Lungs for Carbon Monoxide) 

How is infusing something that's toxic a good thing? Carbon monoxide. That would pretty much make me throw up.

@@dedetudor. Everything is toxic if you take in enough of it. If you drink too much water, you’ll die. Even too much oxygen can make you feel sick and faint. A DLCO-test is of course done in such a way that it’s not harmful for the patient