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Use of exhaled breath condensate (EBC) in the diagnosis of SARS-COV-2 (COVID-19)
  1. Daniel J Ryan1,2,
  2. Sinead Toomey1,
  3. Stephen F Madden3,
  4. Michelle Casey2,
  5. Oscar S Breathnach4,
  6. Patrick G Morris4,
  7. Liam Grogan4,
  8. Peter Branagan2,
  9. Richard W Costello2,
  10. Eoghan De Barra5,
  11. Killian Hurley2,
  12. Cedric Gunaratnam2,
  13. Noel G McElvaney2,
  14. Michael Emmet OBrien2,
  15. Imran Sulaiman2,
  16. Ross K Morgan2,
  17. Bryan T Hennessy1,4
  1. 1 Department of Molecular Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
  2. 2 Department of Respiratory Medicine, Beaumont Hospital, Dublin, Ireland
  3. 3 Data Science Centre, Royal College of Surgeons in Ireland, Dublin, Ireland
  4. 4 Department of Oncology, Beaumont Hospital, Dublin, Ireland
  5. 5 Department of International Health and Tropical Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
  1. Correspondence to Dr Daniel J Ryan, Department of Molecular Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland; danennis100{at}


False negatives from nasopharyngeal swabs (NPS) using reverse transcriptase PCR (RT-PCR) in SARS-CoV-2 are high. Exhaled breath condensate (EBC) contains lower respiratory droplets that may improve detection. We performed EBC RT-PCR for SARS-CoV-2 genes (E, S, N, ORF1ab) on NPS-positive (n=16) and NPS-negative/clinically positive COVID-19 patients (n=15) using two commercial assays. EBC detected SARS-CoV-2 in 93.5% (29/31) using the four genes. Pre-SARS-CoV-2 era controls (n=14) were negative. EBC was positive in NPS negative/clinically positive patients in 66.6% (10/15) using the identical E and S (E/S) gene assay used for NPS, 73.3% (11/15) using the N/ORF1ab assay and 14/15 (93.3%) combined.

  • exhaled airway markers
  • respiratory infection
  • viral infection

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  • DJR and ST are joint first authors.

  • RKM and BTH are joint senior authors.

  • Contributors DR and ST: joint first authors responsible for drafting, conception, design, acquisition, analysis and interpretation. SM: data analysis and interpretation. MC, OB, PGM and LG: data acquisition and analysis. EDB, PB, RWC, KH, CG, NGM, MEO and IS: data acquisition and analysis. RM and BH: joint senior authors responsible for conception, design and drafting of the manuscript for important intellectual content.

  • Funding This study was funded by a Science Foundation Ireland COVID Rapid Response Call grant (20/COV/0109) and the North East Cancer Research and Education Trust (NECRET: Grant no. 1696).

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval Beaumont Hospital Ethics (Medical Research) Committee, Dublin, Ireland (March 31st 2020) REC REF: 20/39.

  • Provenance and peer review Not commissioned; externally peer reviewed.