Reliability of induced sputum test is greater than that of throat swab test for detecting SARS-CoV-2 in patients with COVID-19: A multi-center cross-sectional study. Issue 1 (1st January 2020)

• Record Type: Journal Article
• Authors: Lai, Tianwen; Xiang, Fangfei; Zeng, Jianfeng; Huang, Yingzi; Jia, Liping; Chen, Hui; Wu, Jiayuan; Xie, Jianfeng; Liu, Shuna; Deng, Wei; Zheng, Weiqiang; Huang, Yang; Zhang, Qinfu; Luo, Qingfeng; Mo, Fan; Long, Lieming; Zhang, Wuying; Chen, Wenna; Han, Huanqin
• Is Part Of: Virulence. Volume 11:Issue 1(2020)
• Page Start: 1394
• Page End: 1401
• Publication Date: 2020-01-01
• Subjects: COVID-19 -- reliability -- induced sputum -- throat swab -- SARS-CoV-2; Virulence (Microbiology) -- Periodicals; Bacterial diseases -- Periodicals; Molecular microbiology -- Periodicals; 579.05
• DOI: 10.1080/21505594.2020.1831342
• Languages: English
• ISSNs: 2150-5608

Abstract

ABSTRACT: We previously reported that sputum induction was more sensitive than throat swabs for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in two convalescent coronavirus disease 2019 (COVID-19) patients; however, the value and safety of induced sputum testing require further study. We conducted a prospective multi-center cross-sectional study to compare induced sputum to throat swabs for SARS-CoV-2 detection. Confirmed COVID-19 patients from six hospitals in six cities across China who received one or more negative RT-PCR result for SARS-CoV-2 were enrolled, and paired specimens (induced sputum and throat swabs; 56 cases) were assayed. In three paired samples, both the induced sputum and throat swabs were positive for SARS-CoV-2. The positive rate for induced sputum was significantly higher than for throat swabs both overall (28.6% vs 5.4%, respectively; p < 0.01). Patients were divided according to time span from onset of illness to sample collection into the more-than-30-day (n = 26) and less-than-30-day (n = 30) groups. The positive rate for induced sputum was also significantly higher than for throat swabs in the less-than-30-day group (53.3% vs 10.0%, respectively; p < 0.001). For the more-than-30-day group, all paired samples were negative for SARS-CoV-2. Blood oxygen saturation, respiratory rate, and heart rate remained stable during sputum induction and no staff were infected. Because induced sputum is more reliable and has a lower false-negative rate than throat swabs, we believe induced sputum is more useful for the confirmation of COVID-19 and is safer as a criterion for release from quarantine.