title: Breath analysis in real time by mass spectrometry in chronic obstructive pulmonary disease.
abstract: BACKGROUND
  It has been suggested that exhaled breath contains relevant information on health status.
  
  
  OBJECTIVE
  We hypothesized that a novel mass spectrometry (MS) technique to analyze breath in real time could be useful to differentiate breathprints from chronic obstructive pulmonary disease (COPD) patients and controls (smokers and nonsmokers).
  
  
  METHODS
  We studied 61 participants including 25 COPD patients [Global Initiative for Obstructive Lung Disease (GOLD) stages I-IV], 25 nonsmoking controls and 11 smoking controls. We analyzed their breath by MS in real time. Raw mass spectra were then processed and statistically analyzed.
  
  
  RESULTS
  A panel of discriminating mass-spectral features was identified for COPD (all stages; n = 25) versus healthy nonsmokers (n = 25), COPD (all stages; n = 25) versus healthy smokers (n = 11) and mild COPD (GOLD stages I/II; n = 13) versus severe COPD (GOLD stages III/IV; n = 12). A blind classification (i.e. leave-one-out cross validation) resulted in 96% sensitivity and 72.7% specificity (COPD vs. smoking controls), 88% sensitivity and 92% specificity (COPD vs. nonsmoking controls) and 92.3% sensitivity and 83.3% specificity (GOLD I/II vs. GOLD III/IV). Acetone and indole were identified as two of the discriminating exhaled molecules.
  
  
  CONCLUSIONS
  We conclude that real-time MS may be a useful technique to analyze and characterize the metabolome of exhaled breath. The acquisition of breathprints in a rapid manner may be valuable to support COPD diagnosis and to gain insight into the disease.
authors.affiliation: Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland.
authors.forename: Pablo
authors.initials: P
authors.lastname: Martinez-Lozano Sinues
authors.forename: Lukas
authors.initials: L
authors.lastname: Meier
authors.forename: Christian
authors.initials: C
authors.lastname: Berchtold
authors.forename: Mark
authors.initials: M
authors.lastname: Ivanov
authors.forename: Noriane
authors.initials: N
authors.lastname: Sievi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Camen
authors.forename: Malcolm
authors.initials: M
authors.lastname: Kohler
authors.forename: Renato
authors.initials: R
authors.lastname: Zenobi
mesh_terms: D000328:Adult; D000368:Aged; D001944:Breath Tests / Q000379:methods*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism*; D055815:Young Adult