Breath condensate pH in children with cystic fibrosis and asthma: a new noninvasive marker of airway inflammation?

Chest. 2004 Jun;125(6):2005-10. doi: 10.1378/chest.125.6.2005.


Study objectives: The noninvasive assessment and monitoring of airway inflammation could be important in respiratory disease. The pH of exhaled breath condensate (EBC) is a promising marker. Although pH has been measured in the EBC of adults with inflammatory airway diseases, no study has measured this in children.

Design: This study aimed to assess whether there is a change in pH in the EBC of children with cystic fibrosis (CF) and asthma, and to try to determine whether pH could be used as a marker of airway inflammation. Furthermore, the relationships among EBC pH, severity of disease, and oxidative stress were studied.

Patients and methods: We studied 20 children with CF (mean [+/- SEM] age, 7 +/- 3 years), 20 children with asthma (mean age, 7 +/- 2 years), and 15 age-matched healthy children (mean age, 7 +/- 2 years). The pH of EBC was measured using a pH meter.

Measurements and results: Lower pH values were observed in the EBC of children with CF and asthma compared to control subjects (mean pH, 7.23 +/- 0.03 and 7.42 +/- 0.01 vs 7.85 +/- 0.02, respectively). Furthermore, relationships among EBC pH, severity of asthma, and the presence of an infective exacerbation of CF was found. There was a negative correlation between exhaled pH and exhaled leukotriene B(4) concentrations (r = -0.5; p < 0.005).

Conclusion: We conclude that the measurement of EBC pH may be useful in the evaluation of airway inflammation in children with asthma and CF.

Publication types

  • Comparative Study

MeSH terms

  • Asthma / diagnosis*
  • Breath Tests*
  • Case-Control Studies
  • Child
  • Child, Preschool
  • Cystic Fibrosis / diagnosis*
  • F2-Isoprostanes / analysis
  • Female
  • Humans
  • Hydrogen-Ion Concentration*
  • Inflammation Mediators / analysis*
  • Leukotriene B4 / analysis
  • Male
  • Predictive Value of Tests
  • Probability
  • Prognosis
  • Prospective Studies
  • Reference Values
  • Respiratory Function Tests
  • Risk Assessment
  • Sensitivity and Specificity
  • Severity of Illness Index
  • Statistics, Nonparametric


  • F2-Isoprostanes
  • Inflammation Mediators
  • Leukotriene B4