Cell block preparation on residual ThinPrep sample

The liquid-based cytology system ThinPrep has overcome many of the deficiencies of the conventional Pap test. However, the cytologic appearances of the cells in the liquid-based medium are different and staffs of laboratories adopting the new system have to be specially trained. Even after the training sessions provided by the vendor, the cytology staff still face a sharp learning curve initially. One way to recognize the different appearances of cells in the liquid-based system is to look at paired split-sample cases from the same patient in laboratories offering the test as an adjunct to the conventional Pap test. Laboratories offering direct-to-vial testing may be able to overcome the difficulties with some cases by performing cell block sections of residual materials in the samples. The protocol for making cell blocks and its application in resolving difficulties with high-grade squamous and glandular epithelial lesions is illustrated in this report. Diagn. Cytopathol. 1999; 21:427-431.