I agree with Irishmom4 - Have them check your creatine level. It is a blood test. They may also look at your BUM in a blood test. The creatine is the main thing with kidney issues. I also have PKD (Polysystic Kidney Disease). Crohn's from mom and PKD from dad - gotta love those genes! Normal creatine level is 0.5 to 1.2. I don't really have any problems with my PKD and mine is 0.9. When my dad's got to around 5.0 they started talking dialysis and at around 7.0 he went on dialysis. Thanks to a VERY generous friend he got a kidney in March of 2008 and now his is 0.8! I have never taken MTX, but I have to watch all meds to make sure they don't mess with my kidneys. Good luck!