There was no effect of age on any results, and the various VOCs used were not able to discriminate between classes of smokers, nor were they capable of differentiating according to inhaled steroid use or lack thereof.

One study limitation identified was sputum cell count use as a gold standard for asthma inflammatory phenotype classification.

“We believe that the four compounds identified may become a powerful biochemical signature to discriminate between inflammatory phenotypes,” noted the authors. They recommended that future research explore the utility of VOC monitoring for purposes of tracking responsiveness to maintenance therapies.


Schleich FN, Zanella D, Stefanuto P-H, et al. Exhaled volatile organic compounds are able to discriminate between neutrophilic and eosinophilic asthma [published online April 11, 2019]. Am J Respir Crit Care Med. doi:10.1164/rccm.201811-2210OC