Improvements in cell block processing: The Cell‐Gel method

BACKGROUND The ability to produce adequate cell blocks profoundly impacts the diagnostic usefulness of cytology specimens. Cell blocks are routinely processed from fine‐needle aspiration specimens or concentrated fluid samples. Obtaining directed passes for the sole purpose of producing a cell block is common practice, particularly when the cytopathologist anticipates the need for ancillary immunocytochemical stains and/or molecular studies. METHODS The authors developed an effective and inexpensive process for producing cell blocks that consistently yields abundant cellular material, which they have termed the Cell‐Gel method. This method can be simplified into 3 main steps: 1) preparing the sample; 2) constructing the cell block; and 3) processing the cell block. Highlights of the protocol include using a hemolytic fixative for sample preparation and disposable base molds for cell block construction. RESULTS The cell block failure rate in the current study decreased from 18% with the HistoGel Tube method (January 2014‐December 2014) to 6% with the Cell‐Gel method (January 2015‐December 2016). The authors evaluated 110 cell blocks processed with the HistoGel Tube method and 110 cell blocks processed with the Cell‐Gel method, for a total evaluation of 220 cell blocks. CONCLUSIONS The authors have developed an effective and inexpensive protocol for producing cell blocks that consistently yields abundant cellular material. The Cell‐Gel method uses a hemolytic fixative and disposable base molds to produce adequate cell blocks. When the method was implemented, the cell block failure rate of the study laboratory decreased by approximately 67%. Cancer Cytopathol 2017;125:267–276. © 2016 American Cancer Society.