Utility, feasibility, and socio-demographic considerations in the diagnosis of bacterial respiratory tract infections by GC-IMS breath analysis

Summary Diagnosis of respiratory tract infections, especially in primary care, is typically made on clinical features and in the absence of quick and reliable diagnostic tests. Even in secondary care, where diagnostic microbiology facilities are available, these tests take 24-48 hours to provide an indication of the aetiology. This multicentre study used a portable Gas Chromatography-Ion Mobility Spectrometer for the diagnosis of bacterial RTIs. Breath samples taken from 570 participants with 149 clinically validated bacterial and 421 non-bacterial respiratory tract infections were analysed to distinguish bacterial from non-bacterial RTIs. Through the integration of a sparse logistic regression model, we identified a moderate diagnostic accuracy of 0.73 (95% CI 0·69, 0·77) alongside a sensitivity of 0·85 (95% CI 0·79, 0·91) and a specificity of 0·55 (95% CI 0·50, 0·60). The GC-IMS diagnostic device provides a promising outlook in distinguishing bacterial from non-bacterial respiratory tract infections and was also favourably viewed by participants.