Centrifugal separation of carcinoma or atypical cells in voided urine

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.

Cost efficiency analysis of modern cytocentrifugation methods versus liquid based (Cytyc Thinprep) processing of urinary samples

BACKGROUND/AIMS

Liquid based cytology (LBC) was developed as a replacement for cytocentrifugation in the treatment of cell suspensions. Because accurate data comparing the quality and total cost of modern cytocentrifugation methods versus LBC in non-gynaecological samples are not available, this study was designed to investigate these issues.

METHODS

The study comprised 224 urine samples treated with the Thermo Shandon Cytospin 4 using reusable TPX chambers, disposable Cytofunnels for samples up to 0.5 ml, and disposable Megafunnels for samples up to 6 ml. Each method was compared with the Cytyc Thinprep processing of a paired sample. Quality was assessed by scoring cellularity, fixation, red blood cells, leucocytes, abnormalities of urothelial cells, and suitability for molecular studies. Wage costs, investment, and consumables allowed a "total cost" to be calculated on the basis of 200 specimens/month. Total cost and quality combined were used to calculate an index of total quality (ITQ).

RESULTS

Cytocentrifugation with disposable chambers resulted in a global quality superior to that of Cytyc Thinprep LBC. Preparation and screening times were 2.25 and 1.33-2 times greater when using LBC compared with cytocentrifugation. The total cost each month reached 1960.23 $ to 2833.43 $ for cytocentrifugation methods and 5464.95 $ for Cytyc Thinprep LBC (92.8-178.8% increased cost). ITQ of cytocentrifugation with disposable chambers surpassed that of Cytyc Thinprep LBC (37.25/32.08 and 9.98, respectively).

CONCLUSION

Cytyc Thinprep LBC and cytocentrifugation are both appropriate methods for cytology based molecular studies, but cytocentrifugation remains the quality standard for current treatment of urinary samples because of its lower cost.