Immunocytochemistry in Europe: results of the European Federation of Cytology Societies (EFCS) inquiry

F. Schmitt, B. Cochand‐Priollet, M. Toetsch, B. Davidson, A. Bondi and P. Vielh Immunocytochemistry in Europe: results of the European Federation of Cytology Societies (EFCS) inquiry Objective: This report describes the results of the first chosen topic of the European Federation of Cytology Societies (EFCS) scientific committee, which concerns the application of immunocytochemistry (ICC) to cytological material. While ICC has become an important ancillary method, not only for diagnosis but also to assess prognostic and predictive factors on cytological material, there are many different methodologies used and the lack of standardization has been criticized. This inquiry aimed first to obtain an overview of the techniques used and second to suggest mechanisms for standardization and quality control. Methods: We report the results of 28 replies from 13 countries to a web‐based inquiry into types of specimens, preparations and technical methods. Results: Conventional smears were the preparations most commonly used, followed by cytospins, cell blocks and liquid‐based preparations, in that order. Avidin‐biotin complex, labelled streptavidin‐biotin or peroxidase anti‐peroxidase were used in 61% and enhanced‐polymer technology in 39%. Automated staining techniques were used by 64%. More than half used the same antibody dilutions as histopathology although only 20% used cell blocks. Conclusion: Reduction of variability by using automation, appropriate controls and customized dilution of antibodies according to different samples could improve the quality of ICC and standardize the techniques, along with quality control and quality assurance measures.