I have had at least 3 Pulmonary Function tests, the most recently in April 2015. I have never been told what my percentage of lung function is, even though, I have asked. My question seems to be just brushed off as if the percentage cannot be reliably gauged. Additionally, I have never been told what stage of COPD I am in. When first diagnosed, I was told I had moderate-to-severe Emphysema...moderate doesn't seem bad, but severe does. Is it important for me to have a definite answer? I am thinking that I am at least stage 3 and 50% or less lung function, since I am on O2 24/7. Without O2, if I sit quietly my saturation will be about 87/88. If I move around just a little bit from room-to-room, my saturation drops to about 74. I would just appreciate some opinions. I completed 37 Pulmonary Rehab sessions in early July and have started Phase III Pulmonary Rehab, going for the last 3 weeks, 2-3 times a week.