Because we have the ability to monitor our transplant recipients using the urinary PCR protocol, we can safely minimize tacrolimus exposure over time by monitoring patients non-invasively on a real-time basis. Minimization of immunosuppression over time in a kidney transplant recipient is important in order to prevent or minimize some of the leading causes of kidney graft loss (defined as return to dialysis). Although immunosuppressive medications are excellent at preventing rejection, they do have detrimental effects on the cardiovascular system as well as to the transplant kidney itself. One major cause of kidney graft loss today is chronic allograft nephropathy (CAN). Formerly known as "chronic rejection", CAN has been described as the progressive decline in allograft function that occurs months or years after transplantation, and it is the second leading cause of kidney graft loss. Biopsies of kidney allografts with CAN may show inflammation, fibrosis, glomerulosclerosis, tubular atrophy, and vascular smooth muscle proliferation. The scarring and fibrosis associated with CAN is generally irreversible. A new goal within the modern transplant arena is to prevent CAN from occurring by: