“…There is a fairly substantial literature on protocol biopsies in adult renal transplant recipients, and a smaller literature on pediatric recipients. These studies show a variable incidence of subclinical acute rejection, ranging from 2.6-100%, with many reports in the 25-30% range (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18). There is also a literature demonstrating an incidence of subclinical chronic allograft nephropathy (CAN) (6,8,10,13,14,(17)(18)(19)(20)(21)(22)(23)(24)(25), and a suggestion that the presence of CAN with vasculopathy is a poor prognostic factor for long-term outcome (8).…”