Demand management in urine cytology: a single cytospin slide is sufficient

Current practice in most laboratories stipulates the preparation of duplicate slides for the analysis of urine cytology specimens. This study evaluates whether the duplicate slide is necessary.

Cytospin diagnosis was assessed in three ways. First, all urine cytology preparations from a single month in 1998 were reviewed; the two slides for each case were reported separately and then the two reports on each case were examined for disparity. Second, the slides from all urine cytospin cases indexed as "suspicious" or "malignant" in 1998 were reviewed similarly. Third, 48 cytospin slides from 24 cases were divided into two randomised groups, which were reported and the two reports compared. Finally, the frequency of repeat specimen collection in cases that were deemed inadequate for diagnosis was also assessed.

The cases from a single month (n = 129) were representative of the annual workload and showed no discrepancies of the type: suspicious or malignant/other. Of the 60 suspicious or malignant cases from 1998, there was no disparity in 50. The 10 cases with disparity were all suspicious on one slide and degenerate on the other. In the 24 randomised cases, there was no disparity in 21. The remainder were reported as suspicious or malignant/inadequate (that is, degenerate or acellular). After a report of inadequate for diagnosis, repeat samples were received in only 15% of cases.

Using a single cytospin preparation causes minimal loss of clinically relevant information, but saves substantial resources (approximately 40%/case). A diagnosis of inadequate should prompt the collection of a repeat sample if the service is being used sensibly.