Concordance between original screening and final diagnosis using imager vs. manual screen of cervical liquid-based cytology slides.

Objective: To compare agreement of pathologists and cytotechnologists and technologist productivity before and after implementation of the Cytyc ThinPrep Imager.
Study Design: Using the Cytyc ThinPrep Imaging System, a retrospective analysis was conducted, from the first 6 months in 2004 and in 2005. Total cases in January through June were 79,791 in 2004 and 76,887 in 2005. Data on the number and type of changes from one impression to another were collected in a "confusion matrix". The chi2 test with 1 degree of freedom was used to calculate the significance of the difference between the groups.
Results: Changes in diagnosis were most frequently seen in negative for intraepithelial lesion, atypical squamous cells of undetermined significance and low-grade squamous intraepithelial lesion. Interobserver agreement before the imager (weighted kappa) was 0.74 and after was 0.73.
Conclusions: The number of high-grade lesions detected increased with the imager (p < 0.01). Technologist productivity increased by an average of 2.2 slides/hour.