Cell blocks represent one of several cytology preparations, and play a significant role in providing tissue for ancillary studies, including immunohistochemistry and molecular testing. To the authors' knowledge, there currently is no standardized cell block processing method, and cellular yield often is suboptimal. To overcome the shortcomings of available methods, the authors developed a novel disposable cell block device, XCellent, that uses centrifugation to collect cells into a sample chamber. The sample chamber contains and protects the specimen during tissue processing and also is embedded and sectioned. The primary objectives of the current study were to compare cellular yield, cytomorphological detail, and processing times of HistoGel and XCellent.
Split sample testing of primarily fluid specimens was performed. Group 1 comprised large-volume and/or cloudy fluids and group 2 was residual samples in PreservCyt solution. Two cell blocks, 1 HistoGel cell block and 1 XCellent cell block, were processed from each sample. Cellularity was assessed using computerized image analysis and cytomorphology from 1+ to 3+. Processing times for 16 cell blocks also were recorded.
A total of 50 cell blocks (25 HistoGel samples and 25 XCellent samples) were prepared. On average, cell blocks prepared using XCellent were 371% more cellular than those prepared with HistoGel and had better cytomorphology. Less preparation time was required for bulk processing of XCellent cell blocks (11 minutes) compared with the same quantity of bulk processed using HistoGel (38 minutes).
XCellent provides an alternative cell block processing technique that offers high cellular yield and cytomorphology. In addition, the method uses the standard centrifugation process, which integrates into the existing cytology laboratory workflow.