Morphologic and immunocytochemical performances of effusion cell blocks prepared using 3 different methods.

With increased use of the ThinPrep method for nongynecologic specimens, cell blocks are more commonly prepared by harvesting cells that are fixed in CytoLyt solution. The current study compared morphologic and immunocytochemical performance of effusion cell blocks prepared using CytoLyt-prefixed thrombin clot (CTC) with plasma thrombin clot (PT) and HistoGel (HG) preparation. The study included a total of 25 malignant or benign serous fluids. Three individual cell block materials were simultaneously prepared from each of the 25 effusion specimens using the CTC, PT, or HG method. H&E staining and immunostaining for pancytokeratin (pan-CK), carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA), B72.3, HBME-1, estrogen receptor (ER), progesterone receptor (PR), CD45, CD20, and CD3 were then performed. The CTC preparation revealed compatible cellularity and good cellular details. In addition, CTC cell blocks revealed a similar percentage of cells with positive immunostaining along with the strongest intensity and the least background staining. The CTC method can be used reliably as an adjunct to other preparation techniques.