S urea is 18 mg/l. no albumin/rbc in urine. frequent dark urine. should i see a nephrologist if creatinine raises from 1 to 1.27 in just 3 months?

No: With normal BUN, creatinine, and urinalysis, be thankful for good health. Creatinine varies some from day to day. When I was lifting weights every day, my creatinine ran 1.6-1.8 and that reflected my muscle mass -- a GOOD thing. I am MUCH more concerned about your elevated SGPT; you're getting it worked up, right? Forget about the other labs.