Table 2.

Non-invasive monitoring of airway inflammation: innovative techniques.

Technique	Characteristics
Exhaled breath condensate (EBC)	Non-invasive, not standardized
Measurement of biomolecules	Biomarkers; some biomolecules measured with reference analytical techniques, validation required for most immunoassays
Metabolomics with nuclear magnetic resonance (NMR) spectroscopy	Biomarkers; highly specific, quantitative, analysis of multidimensional data requiring algorithms for pattern recognition
Electronic nose (E-nose)	Non-invasive, not standardized
	Biomarkers; analysis of multidimensional data requiring algorithms for pattern recognition
Breath analysis with gas-chromatography/mass spectrometry (GC/MS)	Biomarkers; highly specific, quantitative