@TidWell I hope you appreciate how nice and polite this reply was, it would have been pretty easy for
@wufabufa to blast you about your ignorance in the matter and call you all kinds of names that question your intelligence.
FWIW my creatinine levels are always way high out of lab range unless I don't train for a couple of days before blood is drawn. I get a full blood panel at least 2x a year. A heavy leg or back workout causes the highest spikes. My personal physician is pretty knowledgeable, a "sports Dr" and the physician for one of our national sports teams. He has never had a problem with my elevated creatinine levels as they do return to normal as per above.
He also has no issues with Creatine supplementation, I take 5-10gr daily (my diet is lacking) and has said that "the whole team" uses it. As far as supplemental or "extra" use the mountain of benefits outweigh the miniscule risks by the largest ratio of almost any substance you can think of besides a scant few things that are immediately essential just to stay alive - oxygen, water etc