Evaluating Donor Kidneys for Transplantation: What to Look for and How to Compile a Meaningful Report

Abstract The severe shortage of kidneys for transplantation has led efforts to expand the kidney donor pool, and to accomplish this goal, kidneys from expanded-criteria donors are being considered today for transplantation. Despite the frequent use of pretransplant biopsies of donor kidneys, no consensus has been reached regarding the prognostic significance of the various pathologic findings. The pathologic evaluation is focused on determining the percentage of globally sclerosed glomeruli; degree of interstitial fibrosis; arteriolar and arterial damage, including degree of vessel wall thickening and the presence/absence of vascular thrombosis; and identifying “significant” glomerular, inflammatory tubulointerstitial or vascular pathology. This information is provided to the transplant surgeon who then makes a determination of whether to transplant or not the deceased- or living-donor kidney in question, if any or a combination of the previously mentioned findings is identified. The present article describes how these donor kidneys should be evaluated morphologically and the impact of the various findings that may be found in deciding whether the kidney should be transplanted and addresses prognostic issues related to transplantation of kidneys exhibiting some of the previously mentioned findings not deemed to be severe enough to prevent transplantation. A review of the different criteria and systems that have been used in the past will be provided to understand how the evaluation process has been viewed by various investigators and the relationship of the various findings to immediate function and prognosis of the grafts. This information is important for surgical pathologists who may be asked to do frozen sections in these kidneys before transplant and/or sign out these specimens in their practices.