Adequacy criteria for voided urine cytology using cytospin preparations

BACKGROUND: Previous studies have suggested that urine cytology adequacy may be related to both specimen volume and cellularity. METHODS: The authors reviewed cytospin preparations from 314 urine specimens (162 voided and 152 instrumented specimens) found to have high-grade urothelial carcinoma on biopsy. RESULTS: The sensitivity of instrumented urine cytology was significantly higher than that of voided cytology (82% vs 25%; P < .001). The cellularity (at least 30 urothelial cells/10 high-power fields [HPF]) of instrumented urine specimens also was significantly higher than that of voided specimens (57% vs 9%; P < .001). The sensitivity of voided urine cytology with a cellularity of 20 to 39 cells per 10 HPF was significantly higher than that of cases with <20 cells per 10 HPF (77% vs 19%; P < .001). The sensitivity decreased with higher cellularity for both types of specimens. The sensitivity of voided cases with a volume of at least 30 mL was higher than that of cases with a volume <30 mL, but this was not statistically significant (31% vs 17%; P = .07). CONCLUSIONS: The sensitivity of voided urine cytology for high-grade urothelial carcinoma is significantly associated with urothelial cellularity but not specimen volume. Both the cellularity and sensitivity of voided urine specimens are less than that of instrumented specimens.