Discriminatory ability of gas chromatography-ion mobility spectrometry to identify patients hospitalised with COVID-19 and predict prognosis

Objectives Rapid diagnostic and prognostic tests for COVID-19 are urgently required. We aimed to evaluate the diagnostic and prognostic ability of breath analysis using gas chromatography-ion mobility spectrometry (GC-IMS) in hospitalised patients with COVID-19. Methods Between February and May 2021, we took one breath sample for analysis using GC-IMS from participants who were admitted to hospital for COVID-19, participants who were admitted to hospital for other respiratory infections, and symptom-free controls, at the University Hospitals of Leicester NHS Trust, UK. Demographic, clinical, and radiological data, including requirement for continuous positive airway pressure (CPAP) ventilation as a marker for severe disease in the COVID-19 group, was collected. Results 113 participants were recruited into the study. 72 (64%) were diagnosed with COVID-19; 20 (18%) diagnosed with another respiratory infection, and 21 (19%) healthy controls. Differentiation between participants with COVID-19 and those with other respiratory tract infections with GC-IMS was highly accurate (sensitivity/specificity: 0.80/0.88; [AUROC] 0.85; 95% confidence intervals: CI [0.74-0.96]). GC-IMS was also moderately accurate at identifying those who subsequently required CPAP (sensitivity/specificity 0.62/0.80; [AUROC] 0.70; 95% CI [0.53-0.87]). Conclusions GC-IMS shows promise as both a diagnostic tool and a predictor of prognosis in hospitalised patients with COVID-19 and should be assessed further in larger studies