How can I improve kidney function? My PCP commented I noticed that the kidney function bumped up with a creatinine from 0.9 to 1.3. We need to repeat this test and if it remains elevated then I will refer you to see a kidney specialist. I am diabetic who recently had the Gastric Bypass to see if I could improve or eliminate my diabetes after 15 years. I am trying to drink lots of water but right now it is a little difficult due to bloating.