Analysis of urine cytology tests in 120 paired cases

OBJECTIVE: To evaluate the smear quality and diagnostic accuracy of ThinPrep processing in comparison to conventional Cytospin technique for urinary cytology. STUDY DESIGN: ThinPrep and Cytospin techniques were retrospectively evaluated by 2 observers in a double-blinded, randomized fashion. Each quality parameter was scored using a semi-quantitative score of 1-3. Diagnostic accuracy indices were calculated with biopsy histology as the gold standard. RESULTS: Quality of cellular distribution and cell preservation were better with Cytospin preparations, whereas ThinPrep smears were superior in terms of stain distribution and cleaner slide background. However, the only significant differences observed were in cellular distribution and a clean background (p < 0.05). Sensitivity and positive and negative predictive values were higher with Cytospin than the ThinPrep technique (90.0%, 94.7% and 71.4% vs. 80.0%, 94.1% and 55.6%, respectively). Conversely, the specificity of both techniques was comparable. CONCLUSION: The Cytospin smears were of better quality than those prepared by the ThinPrep technique. Although both techniques resulted in similar diagnostic accuracies in negative cases, the ThinPrep preparations were not found to be superior to Cytospin smears in diagnosing positive urinary cytology.