Changes in thyroid fine needle aspiration practice during the COVID-19 pandemic.

Purpose to investigate the diagnostic accuracy of a different sample preparation protocol for fine needle aspiration cytology (FNAC) of thyroid nodules established during the COVID-19. Methods from April 2020, conventional smears during FNAC were ceased according to the World Health Organization recommendations due to the increased infection risk for operators, and a new liquid based cytology only protocol (LBC) was adopted. FNACs performed between April 2020 and July 2020 (COVID-19 group) were retrospectively compared with FNACs performed between December 2019 and March 2020 (pre-COVID-19 group). The distribution of the diagnostic categories among SIAPEC-IAP categories and the concordance between cytological and histological results were compared using the Chi-square test. Results 90 and 82 thyroid nodules underwent FNAC in the pre-COVID-19 and COVID-19 group. SIAPEC-IAP classification for samples in the pre-COVID-19 group and COVID-19 group were: TIR1 in 7/90 (8%) and 8/82 (10%), TIR1C in 0/90 (0%) and 6/82 (7%), TIR2 in 59/90 (66%) and 55/82 (67%), TIR3A 8/90 (9%) and 5/82 (6%), TIR3B 1/90 (1%) and 2/82 (3%), TIR4 5/90 (6%) and 1/82 (1%), TIR5 10/90 (12%) and 5/82 (7%) (p=0.081). 12/16 (75%) nodules in the Pre-COVID-19 group and 7/8 (88%) nodules in the COVID-19 group underwent surgery with no significant difference between cytological and histological diagnoses of potentially malignant lesions in the two groups (p=0.931). Conclusion the new LBC only protocol provided similar diagnostic accuracy in comparison with standard protocol, and can be effectively applied during a viral pandemic improving workers health and safety.