Comparison of throat swabs and sputum specimens for viral nucleic acid detection in 52 cases of novel coronavirus (SARS-Cov-2) infected pneumonia (COVID-19)

Background In December 2019, a novel coronavirus (SARS-CoV-2) infected pneumonia (COVID-19) occurred in Wuhan, China. Diagnostic test based on real-time reverse transcription polymerase chain reaction assay (qRT-PCR) was the main means of confirmation, and sample collection was mostly throat swabs, which was easy to miss the diagnosis. It is necessary to seek specimen types with higher detection efficiency and accuracy. Methods Paired specimens of throat swabs and sputum were obtained from 54 cases, and RNA was extracted and tested for 2019-nCoV (equated with SARS-CoV-2) by qRT-PCR assay. Results The positive rates of 2019-nCoV from sputum specimens and throat swabs were 76.9% and 44.2%, respectively. Sputum specimens showed a significantly higher positive rate than throat swabs in detecting viral nucleic acid using qRT-PCR assay (P=0.001). Conclusions The detection rates of 2019-nCoV from sputum specimens are significantly higher than throat swabs. We suggest that sputum would benefit for the detection of 2019-nCoV in patients who produce sputum. The results can facilitate the selection of specimens and increase the accuracy of diagnosis.