Comparison of Throat Washings, Nasopharyngeal Swabs and Oropharyngeal Swabs for Detection of SARS-CoV-2

Viruses. 2021 Apr 10;13(4):653. doi: 10.3390/v13040653.

Abstract

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) RNA is detected by reverse-transcription quantitative real-time PCR (RT-qPCR) from respiratory specimens. This study compares throat washings (TW), nasopharyngeal swabs (NS) and oropharyngeal swabs (OS). A total of 102 samples from 34 adult patients with confirmed SARS-CoV-2 infection were analysed by RT-qPCR with absolute quantification. The median concentrations and diagnostic sensitivities were 5.8×104 copies/mL, 85% (NS), 1.4×104, 79% (OS) and 4.3×103, 85% (TW). Concentration differences were significant between NS and TW (P = 0.019). Saliva (SA) was available from 21 patients (median 3.4×103). OS and TW can be considered for SARS-CoV-2 diagnostics, although with slightly lower concentrations.

Keywords: COVID-19; PCR; RT-qPCR; SARS-CoV-2; diagnostic sensitivity; nasopharyngeal swab; nucleic acid test; oropharyngeal swab; saliva; throat washing.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • COVID-19 / diagnosis*
  • COVID-19 Nucleic Acid Testing
  • Female
  • Humans
  • Male
  • Middle Aged
  • Pharynx / virology*
  • RNA, Viral / analysis
  • RNA, Viral / genetics
  • SARS-CoV-2 / genetics
  • SARS-CoV-2 / isolation & purification*
  • Saliva / virology
  • Sensitivity and Specificity
  • Specimen Handling / methods*
  • Viral Load
  • Young Adult

Substances

  • RNA, Viral