Significance of nucleic acid positive anal swab in COVID-19 patients

Abstract Aim We compared the clinical characteristics of patients with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) positive and negative anal swabs during coronavirus disease 2019 (COVID-19) recovery and investigated the clinical significance and influence factors of anal swab detection. Methods This study retrospectively analyzed 23 moderate COVID-19 patients in the recovery phase. They were divided into anal swab positive group (n = 13) (negative for pharyngeal swabs but positive for anal swabs) and anal swab negative group (n = 10) (negative for pharyngeal and anal swabs). The epidemiology, clinical symptoms, time of pharyngeal swabs turning negative, and laboratory results were compared. Results The time of pharyngeal swabs turning negative in the anal swab positive group was 6 (5–8.5) days, significantly longer than that in the anal swab negative group (1 (1–4.25) days), P = 0.0002). The platelet count of the anal swab positive group was significantly lower than that of the anal swab negative group (198 (135–235) × 109/L vs 240.5 (227–264.75) × 109/L, P = 0.0248). No significant difference was observed between the two groups in other variables. Conclusions The time of pharyngeal swab turning negative in anal swab positive patients is longer than that in anal swab negative patients. The platelet count can be used as an indicator for viral infection evaluation. For patients with a longer time of pharyngeal swabs turning negative, the combined testing of the anal swab and platelet counts may help to avoid pharyngeal swab false negatives, premature discharge, and the possibility of fecal-oral transmission.