Aim: The aim of the study was to assess the clinical value of urinary sediment cytology (USC) by use of phase-contrast microscopy in the evaluation of acute tubular necrosis (ATN) during the early period after kidney transplantation. The study was performed at the Cytology Laboratory, Department of Nephrology and Dialysis, Clinical Hospital Center Rijeka, Croatia.
Patients and methods: Patients included 141 kidney recipients, 99 male and 42 female, mean age 40 +/- 13 (range 8-72) years, who had received kidney allograft during the period of ten years, and who were treated at the University Department of Internal Medicine, Rijeka Clinical Hospital Center. The majority of patients (76%) had received cadaveric kidneys. Urinary sediment was analyzed for the presence of renal tubular cells, isomorphic erythrocytes, lymphocytes, casts and debris. Renal tubular cells on USC were recognized as the most constant sign of ATN. The presence of lymphocytes should arise suspicion of rejection.
Main outcome measures: A typical cytologic profile of acute tubular lesion consists of tubular cells, isomorphic erythrocytes, casts, cellular and/or amorphic debris.
Results: USC by use of phase contrast microscopy is confirmed as a method of a very high sensitivity (82%) and specificity (93%) in the evaluation of ATN in transplanted kidney patients during early post-transplantation period. In situations of coexistence of several causes of allograft dysfunction, "mixed" cytologic pictures were frequently created, from which it is difficult or almost impossible to identify the actual cause of kidney dysfunction. In these cases, the final judgment should be made solely by histologic evaluation, which still represents the gold standard in the evaluation of kidney allograft dysfunction.
Conclusion: Serial USC, when thoroughly examined using phase-contrast microscopy, is a simple, noninvasive, fast, easily repeatable and inexpensive diagnostic method of high sensitivity and specificity in the evaluation of ATN during the early phase after kidney transplantation.