If you are under 20%, why not start the transplant eval? The sooner you can get on the list, the more time you accumulate. The transplant eval process wasn't so bad. My potential donor had to go through a lot more than I did. I had to stop my ACE inhibitor last year after 6 or 7 years because of high potassium levels (were always in the 5 range). I have quickly digressed from the mid 20's to 15% GFR after switching to a beta blocker... Still hoping for a pre-emptive transplant, so I haven't a fistula or catheter placed yet.