Comparison of two preparatory techniques for urine cytology.
 Two methods of preparation of urine for cytology were compared retrospectively.
 In method 1 cells in the urine were fixed after the preparation of the smear; in method 2 the cells were fixed before smear preparation.
 Urine cytology reports were correlated with subsequent histological analysis.
 The specificities of urine cytology using both methods were high (99%).
 The sensitivity using method 1 was 87%; using method 2 it was 65%.
 This difference was significant.
 The cell preparation technique therefore significantly changes the sensitivity of urine cytology.
 Cellular fixation after smear preparation is preferable to smear preparation after fixation.
