Evaluation of a centrifuge method and thin-layer preparation in urine cytology

To evaluate and compare the quality and cost of urine cytology using the Cytospin method (Shandon, ThermoElectron Corporation, Waltham, Massachusetts, U.S.A.) and the AutoCyte PREP (TriPath Imaging, Burlington, North Carolina, U.S.A.) in a general laboratory.

A study of differences between the Cytospin method and AutoCyte PREP in the areas of specimen preparation, staining, number and quality of diagnostic cells, background, screener preference, and cost was undertaken over a 3-month period in 2000. Sixty fresh voided urine samples from 25 patients with known transitional cell carcinoma were prepared by the Cytospin method and the AutoCyte PREP according to the manufacturers' instructions.

The Cytospin method had longer preparation time but shorter screening time than the AutoCyte PREP. The number of diagnostic cells was higher in the Cytospin method. Fixation quality and staining clarity were better in the Cytospin method. Qualitative assessment of cell arrangements, cell and nuclear size and shape, nuclear/cytoplasmic ratio and nuclear membrane irregularity showed no significant differences between the 2 methods. Cellular details and nuclear chromatin patterns were clearer and better preserved in the Cytospin method, but the AutoCyte PREP showed less blood and inflammatory cells and debris.

In the majority of cases the screeners preferred the Cytospin method due to its better overall cytologic quality. However, the amount of blood, inflammation and debris was much lower in the AutoCyte PREP. This reduced the need to make a second, diluted specimen and made turnaround time faster. The AutoCyte PREP was 7 times more expensive than the Cytospin method.