My GFR is 18 Bun is 31 Creatinine Serum 1.5 Would this be Stage 3 or 4 Kidney Disease?

The numbers that you provide do not make any sense to me. I suggest that you go to our web site and re-calculate you estimated glomerular filtration rate (eGFR). You may do this at: http://kidney.org/professionals/kdoqi/gfr_calculator.cfm The numbers you provide to not seem correct.