A Concise Review of Exhaled Breath Testing for Respiratory Clinicians and Researchers

Exhaled breath contains an extensive reservoir of biomolecules. The collection of exhaled breath is non-invasive and low-risk. Therefore, its testing is an appealing strategy for the discovery of biomarkers of respiratory diseases. In this concise review, we summarize the evidence of exhaled breath tests for airways diseases and respiratory infections. An overview of breath collection methods in both spontaneously-breathing individuals and those receiving mechanical ventilation is outlined. We also highlight the challenges in exhaled breath testing and areas for future research.