The GFR is a mathematical calculation based on creatinine, gender, and ethnic background. It's not as accurate as a 24 hour urine test, but obviously more convenient once a pattern has been established. Your numbers are close to mine. My creatinine has been in the 2.2-2.4 range for years. My nephrologist is concerned that I stay in that range, and is not so concerned with BUN, which fluctuates more than the other numbers.

Only one time has my GFR dipped below 20. The upside is that it qualified me to pre-emptively get accepted on to the kidney transplant list. I am inactive status, since I'm relatively stable, but am gaining seniority for when/if I need to transfer to active status. It was not my nephrologist who suggested I get on the transplant list; it was a nurse from my insurance company.