I had a kidney transplant 4 weeks ago. my creatine post transplant was 0.5. since then it has steadily risen to 1.0. is this a sign of rejection?

Kid TRANSPLANT FX: You received a single adult kidney and single kidneys provide 50 percent of the creatinine clearance that two healthy kidneys provide. In a 56 yo person a normal serum creatinine value would be 0.9-1.1, depending upon muscle mass. Your earlier creatinine value reflected hyper-hydration, which is usual post-transplant from IV fluids. The rise of creatinine to 1.0 is equilibration, not rejection.