In children, the early detection and accurate diagnosis of acute renal
allograft rejection (AR) may be difficult. A delay in the diagnosis a
nd treatment of AR might engender a poor outcome. Core needle biopsy i
s diagnostic but invasive. However, only a few less-invasive means to
diagnose AR are sufficiently accurate to warrant their routine use. On
e such method is urine cytology. Investigators have demonstrated in mo
re than 800 patients that urine cytology is simple and reliable for di
agnosing graft failure. These observations may be important for childr
en, for whom a non-invasive, accurate, and easily repeated indicator o
f AR may be particularly useful. While not a substitute for transplant
biopsy, urine cytology may reduce diagnostic uncertainty and indicate
the need for core needle sampling in a timely manner.