I just got some repeat routine blood tests back, and noticed that my serum creatinine level has jumped from 0.82 mg/dl to 1.05 mg/dl - an increase of around 27% - in the space of 12 weeks. I am an otherwise healthy 19 year old male, but I have noticed a mild ache in the middle of my back to the right of my spine over the past couple of weeks. When I saw the doctor before my most recent blood test, he was certain that the ache was muscular, but I am concerned that the creatinine level increase is coincidental with the ache in my right back, and so I am worried that I am suffering from some occult kidney disorder.
I notice that my urine sometimes produces bubbles on the surface of the toilet water, depending on how dilute it is, but I do not know what "frothy urine" due to proteinuria would look like, so my worries are compounded by that uncertainty, too.
Before I return to the doctor (which I may not do until October), does anyone have any idea what could cause the creatinine level seemingly to increase like that?
All the best,