Description of a new biosafe procedure for cytological specimens from patients with COVID-19 processed by liquid-based preparations

Background: Coronavirus disease 2019 is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and represents the causative agent of a potentially fatal disease. The spread of the infection and the severe clinical disease have led to the widespread adoption of social distancing measures. Special attention and efforts to protect or reduce transmission have been applied at all social levels, including health care operators. Hence, this reports focuses on the description of a new protocol for the safe management of cytological samples processed by liquid-based cytology (LBC) with an evaluation of the changes in terms of morphology and immunoreactivity. Methods: From March 11 to April 25, 2020, 414 cytological cases suspicious for SARS-CoV-2 were processed with a new virus-inactivating method suggested by Hologic, Inc, for all LBC specimens. Results: The samples showed an increased amount of fibrin in the background. A slight decrease in cellular size was also observed in comparison with the standard method of preparation. Nonetheless, the nuclear details of the neoplastic cells were well identified, and the immunoreactivity of the majority of those cells was maintained. The cell blocks did not show significant differences in morphology, immunoreactivity, or nucleic acid stability. Conclusions: Despite some minor changes in the morphology of the cells, the results of this study highlight that the adoption of the new protocol for the biosafety of LBC-processed samples in pathology laboratories is important for minimizing the risk for personnel, trainees, and cytopathologists without impairing the diagnostic efficacy of the technique.