Diagnostic impact of safety protocols for processing peritoneal washing specimens during the global pandemic of coronavirus disease 2019: A comparative study from 195 cytological samples

Background: The global pandemic of the coronavirus disease 2019 represents a major concern for health services worldwide, and has also induced major changes in cytopathology practice. Aim: We aimed to verify the diagnostic performance of cytological evaluation under a new safety protocol during the pandemic compared to the standard pre-pandemic procedure. We also aimed to assess how cytological diagnoses and sampling were impacted during the pandemic period compared to the pandemic-free period in 2019. Materials and methods: Cytological samples of peritoneal washings taken during the first 10 months of the pandemic emergency in Italy (March 11, 2020 to January 11, 2021) were compared to samples from the preceding 10-month time frame (May 11, 2019 to March 10, 2020). Results: One hundred ninety-five specimens were analysed in the present study. We observed no noticeable differences in cytological diagnoses during the pandemic period compared to the pre-pandemic period. The case numbers by diagnostic category for the pre-pandemic vs pandemic periods, respectively, were as follows: non-diagnostic, 0 vs 0 cases; negative for malignancy, 86 vs 52 cases; atypia of uncertain significance, 7 vs 1 cases; suspicious for malignancy, 0 vs 2 cases; malignant, 42 vs 4 cases. Conclusion: While a consistent reduction in the number of cytological examinations has been observed during the COVID-19 period, our institutional safety protocol for processing cytological samples did not affect the diagnostic reliability of peritoneal washing cytology.