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)

Clin Chem Lab Med. 2020 Jun 25;58(7):1089-1094. doi: 10.1515/cclm-2020-0187.

Abstract

Objectives In December 2019, a novel coronavirus (SARS-CoV-2)-infected pneumonia (COVID-19) occurred in Wuhan, China. Laboratory-based diagnostic tests utilized real-time reverse transcriptase polymerase chain reaction (RT-PCR) on throat samples. This study evaluated the diagnostic value to analyzing throat and sputum samples in order to improve accuracy and detection efficiency. 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 the RT-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 the RT-PCR assay (p = 0.001). Conclusions The detection rates of 2019-nCoV from sputum specimens were significantly higher than those from 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.

Keywords: COVID-19; SARS-Cov-2; sputum specimens; throat swabs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Betacoronavirus / genetics
  • Betacoronavirus / pathogenicity
  • COVID-19
  • China
  • Clinical Laboratory Techniques / methods
  • Coronavirus / genetics
  • Coronavirus / pathogenicity
  • Coronavirus Infections / diagnosis*
  • Coronavirus Infections / genetics*
  • Diagnostic Tests, Routine / methods
  • Female
  • Humans
  • Male
  • Middle Aged
  • Pandemics
  • Pharynx / virology
  • Pneumonia, Viral / diagnosis*
  • Pneumonia, Viral / genetics*
  • Real-Time Polymerase Chain Reaction / methods
  • SARS Virus / genetics
  • SARS Virus / pathogenicity
  • SARS-CoV-2
  • Specimen Handling / methods*
  • Sputum