URINE CYTOLOGY AND THE DIAGNOSIS OF RENAL-ALLOGRAFT REJECTION .1. STUDIES USING CONVENTIONAL STAINING

OBJECTIVE: To determine the reproducibility and validity of urine cyto logy for the diagnosis of acute renal allograft rejection (AX). STUDY DESIGN: We conducted a blind, prospective study of 10 renal allograft recipients. Freshly voided aliquots of urine were obtained on each hos pital day and at each outpatient visit for 17 mean of 52.8+/-26.2 (SD) days following transplantation. The samples were prepared by cytocent rifugation and then stained by a modified Papanicolaou method. To dete rmine interobserver reproducibility, the differential cell counts of t wo blinded cytopathologists were compared. A cytodiagnosis of AR was m ade when the urine sample contained <55% neutrophils and >20% lymphocy tes. To determine the validity of the cytology, the result was compare d to the histologic and clinical diagnoses. Biopsies were obtained one hour following vascular anastomosis and at the time of graft dysfunct ion and were scored by two blinded pathologists according to the Banff classification. The clinical diagnosis was determined by a retrospect ive review conducted by four blinded clinicians. RESULTS: Tile interop erator reading of urine cytology was more reproducible than histology, with kappa values of 0.40+/-0.15 (SE) and 0.21+/-0.10 (SE), respectiv ely Urine cytology aas accurate for the diagnosis of AX, with a sensit ivity of 80% and a specificity of 96% as compared to the clinical and histologic findings. CONCLUSION: Our observations support the claim th at urine cytology is useful for diagnosing AR.