Chest
Original ResearchNormative Data for pH of Exhaled Breath Condensate
Section snippets
Subjects
Self-described healthy volunteers were recruited from the area surrounding the University of Virginia in the United States. This is a mixed community of urban, suburban, and rural families. To ensure that the population would serve as the most useful control group, subjects were excluded from the study if they affirmed on screening that they smoked tobacco or had any of the following symptoms or diseases: chronic cough, recurrent or chronic wheeze, COPD, emphysema, chronic bronchitis, cystic
Results
Four hundred twelve subjects were enrolled and provided a single EBC sample for this study. The subject population is described in Table 2. Of the 412 subjects enrolled, 404 provided sample volumes sufficient for EBC pH assay, a success rate > 98%.
The median EBC pH of this healthy population was 8.0 with interquartile (25 to 75%) range of 7.8 to 8.1 (Fig 1). The maximum EBC pH was 8.4, and the minimum pH was 4.5. The values were the same for female patients (median, 8.0; interquartile range,
Discussion
In this study, we have demonstrated that in healthy subjects, the median, gas-standardized EBC pH is 8.0 with an interquartile range of 7.8 to 8.1. The data are tightly clustered in a mildly nonparametric bell curve. This normal range provides additional context to the published data revealing prominently lower values in patients with multiple respiratory disease states (with EBC pH often in the pH 4 to 6 range).123578121314 Our data present a range that is slightly higher than that from
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Cited by (0)
Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).
Dr. Hunt is a co-founder of Respiratory Research, Inc, the company that manufactures the EBC collectors used in this study. This company and the University of Virginia own patents relating to collection of and pH measurement in EBC.