Diagnostic efficacy and validity of the ThinPrep method in cervical cytology

To examine the efficacy of the ThinPrep method, an automated, fluid-based technique for the collection and preparation of exfoliated and aspirated cells in cervical cytology.

A total of 251 patients participated. From each patient a sample was obtained by scraping with a wooden spatula, split and prepared with both conventional Papanicolaou and ThinPrep methods. In the ThinPrep processor, epithelial cells were homogenized in a vial of preservative solution and randomly sampled onto a microscopic slide. From a single vial of sample suspension a series of 10 ThinPrep slides of the same quality were made. All cells were concentrated within an approximately 20-mm-diameter circle in a uniform, thin layer on the ThinPrep slide.

Twenty-five percent of the screening area, 10% of the epithelial cells observed and 50% of the screening time were required to arrive at a final diagnosis as compared with the Papanicolaou smear. Virtually complete concurrence was ascertained between the Papanicolaou and ThinPrep diagnoses, for direct agreement of 95.3% and agreement within one diagnostic grade of 99.5%.

An overall improvement was ascertained in the preparation of microscopic slides and the recognition of abnormal cells with the ThinPrep method.