I think it's the creatinine, not creatine, in regards to measuring kidney function. Mine was normal pre-cancer, had kidney failure as a result of TPF chemo, and my new baseline is now 2.3 with stage 4 CKD, although it was up to 7 several times, with acute kidney failure, and is when they start considering dialysis, maybe even before, but thankfully my numbers stabilized back. There are many other factors involved, not much that may be done once damaged. I'm told to stay away from ibuprofen, Tylenol, not gain any weight when I went up to 200lbs last summer, no contrast with CT or MRI. Maybe see a nephrologist also.

CPK, Creatine Phosphoskinase Test, measures the enzyme in the blood, which usually is supplied to the heart, brain, skeletal muscles. Creatine is the chemical to supply energy to these muscles.