I’m not sure there is any way to answer your question. The serum creatinine has many factors that can affect an individual test including variability in the individual blood testing, dehydration, medications, diet and many other factors. You have mentioned many of these factors that may all have an effect. I can only suggest continued observation and leading a healthy life-style. I suggest that you discuss your concerns with his nephrologist and try to understand the testing that has been done and further testing that could be done to clarify the issue.