Use of exhaled breath condensate (EBC) in the diagnosis of SARS-COV-2 (COVID-19)
Daniel J Ryan, Sinéad Toomey, Stephen F. Madden, Michelle Casey, Oscar S. Breathnach, Patrick G. Morris, Liam Grogan, Peter Branagan, Richard W. Costello, Eoghan de Barra, Killian Hurley, Cedric Gunaratnam, Noel G. McElvaney, Michael Emmet OBrien, Imran Sulaiman, Ross Morgan, Bryan T. Hennessy
Abstract
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.