Diagnosis of COVID-19 by exhaled breath analysis using gas chromatography-mass spectrometry

Background The ongoing COVID-19 pandemic has claimed over two and a half million lives worldwide so far. SARS-CoV-2 infection is perceived to be seasonally recurrent and a rapid non-invasive biomarker to accurately diagnose patients early-on in their disease course will be necessary to meet the operational demands for COVID-19 control in the coming years.

Objective To evaluate the role of exhaled breath volatile biomarkers in identifying patients with suspected or confirmed COVID-19 infection, based on their underlying PCR status and clinical probability.

Methods A prospective, real-world, observational study recruiting adult patients with suspected or confirmed COVID-19 infection. Breath samples were collected using a standard breath collection bag, modified with appropriate filters to comply with local infection control recommendations and samples were analysed using gas chromatography-mass spectrometry (TD-GC-MS).

Findings 81 patients were recruited between April 29th to July 10th, 2020, of whom 52/81 (64%) tested positive for COVID-19 by RT-PCR. A regression analysis identified a set of seven exhaled breath features (benzaldehyde, 1-propanol, 3, 6-methylundecane, camphene, beta-cubebene, Iodobenzene, and an unidentified compound) that separated PCR positive patients with an area under the curve (AUC): 0.836, sensitivity: 68%, specificity: 85%.

Conclusions GC-MS detected exhaled breath biomarkers were able to identify PCR positive COVID-19 patients. External replication of these compounds is warranted to validate these results.