Conventional liquid-based techniques versus Cytyc Thinprep processing of urinary samples: a qualitative approach.

Background: The aim of our study was to objectively compare Cytyc Thinprep and other methods of obtaining thin layer cytologic preparations (cytocentrifugation, direct smearing and Millipore filtration) in urine cytopathology.

Methods: Thinprep slides were compared to direct smears in 79 cases. Cytocentrifugation carried out with the Thermo Shandon Cytospin 4 was compared to Thinprep in 106 cases, and comparison with Millipore filtration followed by blotting was obtained in 22 cases. Quality was assessed by scoring cellularity, fixation, red blood cells, leukocytes and nuclear abnormalities.

Results: The data show that 1) smearing allows good overall results to be obtained, 2) Cytocentrifugation with reusable TPX chambers should be avoided, 3) Cytocentrifugation using disposable chambers (Cytofunnels or Megafunnel chambers) gives excellent results equalling or surpassing Thinprep and 4) Millipore filtration should be avoided, owing to its poor global quality. Despite differences in quality, the techniques studied have no impact on the diagnostic accuracy as evaluated by the rate of abnormalities.

Conclusion: We conclude that conventional methods such as cytocentrifugation remain the most appropriate ones for current treatment of urinary samples. Cytyc Thinprep processing, owing to its cost, could be used essentially for cytology-based molecular studies.