[Analysis of the positive rate of anal swab nucleic acid test and clinical characteristics in patients with different severity of coronavirus disease 2019].

Objective: To compared the positive rate of anal swab nucleic acid test and clinical characteristics of critical and general coronavirus disease 2019 (COVID-19) patients.

Methods: Clinical data of 18 patients with COVID-19 admitted to the First People's Hospital of Lianyungang City from February to March 2020 were retrospectively analyzed. The patients were divided into general group (n = 11) and critical ill group (n = 7) according to the severity of the disease. The differences of gender, age, epidemiological characteristics, fever duration after admission, underlaying disease, positive rate of anal swab nucleic acid test at admission and two times of negative pharyngeal swab test were compared between the two groups.

Results: There were no significant differences in gender, age, fever duration after admission or underlaying disease between the two groups. The number of anorectal swab positive cases in critically ill group was significantly higher than that in general group (cases: 4 vs. 1, P = 0.047). After two negative pharyngeal swab nucleic acid test, the number of anal swab positive cases in critical illness group was still higher than that in general group (cases: 2 vs. 0), but the difference was not statistically significant (P = 0.137). The number of non-local infection in critical ill group was significantly higher than that in general group (cases: 4 vs. 0, P = 0.047). All of the 4 non-local infected patients had a history of living in Wuhan.

Conclusions: The patients with anorectal swab nucleic acid positive may have a more serious condition. It may be a risk to transfer ill patients out of the isolation ward by the criteria of only two times of negative pharyngeal swab nucleic acid test. Patients returning to our city after infection in Wuhan may be more serious.