Evaluation of exhaled breath condensate pH as a biomarker for COPD

William MacNee, Stephen I. Rennard, John F. Hunt, Lisa D. Edwards, Bruce E. Miller, Nicholas W. Locantore, Ruth Tal-Singer

Research output: Contribution to journalArticlepeer-review

41 Scopus citations


Introduction: We assessed the utility of EBC pH as a biomarker in COPD in a large cohort of well-characterised individuals with COPD and control subjects from the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) study. We also determined short term reproducibility and the response of EBC to oral prednisolone. Methods: EBC was collected with R-TubesTM, using techniques for sampling and measurement that have been shown to be reproducible. Results: EBC pH was lower in COPD (n = 676, 7.29 ± SD 0.60) and in smoking controls (n = 31, 7.18 ± 0.85), compared with non-smoking controls (n = 50, 7.59 ± 0.44, p = 0.0008 and 0.0033 respectively), but was not different between COPD and smoking controls. There was no relationship between EBC pH and disease severity, as assessed by the percent predicted FEV1, nor with airway inflammation as assessed by sputum leukocyte counts. Treatment with 20 mg.day-1 prednisolone for 4 weeks did not change EBC pH. Conclusion: EBC pH is lower in COPD than in healthy control non-smokers, but does not differentiate COPD from smokers without COPD, relate to disease severity or to airway inflammation, and does not respond to corticosteroids. EBC pH therefore does not appear to be a useful biomarker in COPD.

Original languageEnglish (US)
Pages (from-to)1037-1045
Number of pages9
JournalRespiratory Medicine
Issue number7
StatePublished - Jul 2011


  • Biomarkers
  • COPD
  • Exhaled breath condensate

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


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