Abstract: Objective To analyze the detection rate and clinical value of SARS-CoV-2 nucleic acid in anal swab specimen from the convalescent patients with novel coronavirus infection (COVID-19). Methods SARS-CoV-2 nucleic acid samples were detected in convalescent patients with COVID-19 including sputum, pharyngeal swabs and anal swabs specimens. The nucleic acid positive rates of three types of specimens were analyzed. Meanwhile, the nucleic acid detection rates of sputum and pharyngeal swab specimens were analyzed in patients with the positive nucleic acid of anal swab virus. Results A total of 156 samples were collected from 50 patients with COVID 19. The positive for SARS-CoV-2 nucleic acid was 8 (19.5%) in 41 sputum samples. The positive for SARS-CoV-2 nucleic acid was 6 (10.9%) in 55 throat swab samples. The positive for SARS-CoV-2 nucleic acid was 11 (18.3%) in 60 anal swab specimen. Among the 50 convalescent patients with COVID-19, sputum, pharyngeal swabs and anal swab samples were 8 cases (19.5%), 6 cases (12.0%) and 10 cases (20.0%), respectively. In 10 patients with positive anal swab detection, 9 cases were found negative in the respiratory tract specimens. Conclusion The positive detection rate of SARS-CoV-2 nucleic acid is higher in anal swab specimen than that of laryngeal swabs and sputum specimens of the convalescent patients with COVID-19. When SARS-CoV-2 nucleic acid is negative in respiratory tract specimens, the anal swab specimen should be detected in the recovery period, which can be used as leaving hospital standard or isolation standard.

Key words: pneumonia, viral, coronavirus, convalescence, COVID-19, SARS-CoV-2, anal swab, nucleic acid detection