I have been reading your post about the oximeter used to check oxygen sats. I have one from amazon (choicemmed). I have checked it with one at the doctor's office and it seems to do good. The thing is that most of the time when I use it it will give a reading and then start to rise or lower. For instance If I put it on and it reads 88, and then it begins so rise and usually ends up reading 92-93. So I wonder which one is right, the first number of 88 or the 92-93?