Breath-Based Pathogen Detection Technologies for Diagnosing Respiratory Infections: A Scoping Review Protocol

<ns7:p>Accurate and rapid diagnostics are essential for reducing the global burden of respiratory diseases. However, conventional methods have significant limitations. Sputum, while commonly used, presents challenges such as difficulty in collection, variable sample quality, and limited applicability across patient groups. Exhaled breath is a promising diagnostic specimen for direct pathogen detection, while potentially providing insights into infectiousness. The landscape of breath-based detection technologies is rapidly expanding, driven by technological advancements and a growing interest in non-invasive, user-friendly sampling methods. As the field matures, it is important to comprehensively map current innovations with clinical potential, identify use cases and technological gaps, and assess diagnostic accuracy across various respiratory pathogens and syndromes. This scoping review will systematically map breath-based technologies for direct pathogen capture and/or detection, detailing methodologies, diagnostic performance, strengths, limitations, and potential for clinical adoption. The scoping review will be reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension Scoping Reviews (PRISMA-ScR) guidelines. We will systematically search MEDLINE (via PubMed), Embase, and Web of Science for articles published between 1 January 2015 and 19 February 2025, supplemented by grey literature to gather additional information on identified technologies. We will include pre-clinical and clinical studies utilizing exhaled breath aerosol (XBA) or exhaled breath condensate (EBC) for pathogen capture and/or detection. We will exclude studies without performance data from contrived and/or clinical samples. We will also exclude studies reporting solely on volatile organic compounds (VOC)-based detection due to their limited diagnostic specificity. Two reviewers will independently perform title and abstract screening followed by full-text screening, discrepancies will be resolved by consensus or a third reviewer. Data extraction will be conducted by one reviewer and verified by another. Data synthesis will include tabular presentation and narrative summary. Risk of bias assessment will not be included.</ns7:p>