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Effect of contrast media on urinary cytopathology specimens

  • S. Frees,
  • S. Bidnur,
  • M. Metcalfe,
  • P. Raven,
  • C. Chavez-Munoz,
  • I. Moskalev,
  • Ladan Fazli,
  • Alan So

Publication: Can Urol Assoc J., August 2016, Pages 228-233


Urological dogma dictates that washings collected from the urinary tract for cytological assessment must be performed without interference from contrast agents that may alter cellular integrity and diagnostic interpretation. In practice, the initial contrast used to outline the upper tracts is commonly discarded with subsequent saline washings sent for cytology. We hypothesize that contrast washings do not affect the morphology of urothelial carcinoma cells or the integrity of cytology interpretation.


Samples obtained from (1) human bladder cell lines; (2) urine from a human xenograft bladder cancer model using UC-3 cells; and (3) patients with urothelial carcinoma were subjected to various experimental solutions (water, saline, urine, and dilutions of contrast media) for different exposure times. After exposure to various different solutions, samples underwent cytological analysis to assess morphologic and degenerative changes.


No cytological differences were seen when cells were exposed to ionic, hyperosmolar, or non-ionic low-osmolar contrast agents for any exposures up to five minutes. Cells exposed to mixtures of contrast agents and urine also demonstrated no evidence of degenerative change. Cells exposed to water for greater than one minute demonstrated significant hydropic degeneration impacting cytological interpretation. At 40 minutes or later, all reagents caused severe degeneration when evaluating urine samples from the mouse bladder cancer model and from patients undergoing urothelial carcinoma. 

Commonly used contrast agents have no effect on urinary cytology up to five minutes. Contrast washings of the urinary tract should not be discarded and can be sent for cytological diagnosis if fixed within this time period.

Commented by Piotr Chlosta

Study suggests that commonly used contrast agents do not alter urothelial cell morphology and do not impair cytopathological analysis when fixation is within 5 minutes following exposure, questioning common recommendation of collecting washings from urinary tract before contrast agent administration.