Why carbon monoxide used in breathing testing , dlco reading in spirometry

I found out a while back that the spirometry test, the part that tests dlco, involves carbon monoxide. Does anyone know what the other gas with it is, the tracer gas?
I actually didnt notice I was being given gas at first. I normally read everything about a dr test before taking it, n the times i havent, thinking... oh its nothing, sounds simple enough... it always turns out to be the craziest medical idea ever. Such as when i thought i was just doing a videonystagmography test n didnt expect the part where air was blown into my ears n the actual GOAL was to cause nystagmus n dizziness, as a test. Not to test for them, but to cause them to test for things such as death of brainstem. Which EASILY has obvious other ways of finding out about. This is mainly something that should just be saved for a coma but ent's use this test on anyone w ear problems n dizziness. Its that, if they do not get dizziness n nystagmus from it, THEN the results are abnormal. This test actually solves nothing for people who have dizziness problems ALREADY, only worsens them n is completely unnatural to blow lg amts of air into the ears. I feel ridiculous for even listening n going along w such a thing. As the giddy, almost maniacally cackling dr stood above me, i think farting a few times bc she got so overexcited by it. So its actually supposed to cause dizziness n nystagmus, for their test. No joke, in descriptions everywhere. Bc if it doesnt, then there may be a brainstem problem. Does anyone think this is insane? And what are your opinions on this carbon monoxide test? I thought it was just air blowing at first. Did anyone feel any different from it? N why do they choose carbon monoxide n whatever other chemical? Whats supposed to be so great about it for use in breathing testing? Any real, logical reason? Tweet