Investigations on the variability of breath gas sampling using PTR-MS
B Thekedar1, W Szymczak, V Höllriegl
1Institute of Radiation Protection, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany.
Journal of Breath Research
|March 9, 2011
Summary
Breath gas analysis shows promise for medical diagnostics. However, long-term breath sample collection (15-70 days) introduces significant variability in volatile organic compounds (VOCs), hindering reliable disease biomarker detection.
Area of Science:
- Medical Diagnostics
- Analytical Chemistry
- Biomarker Discovery
Background:
- Breath gas analysis offers a non-invasive method for early disease diagnosis and therapy monitoring.
- Identifying disease-specific biomarkers in exhaled breath is crucial for developing diagnostic tools.
- Low measurement variability of exhaled volatile organic compounds (VOCs) is essential for reliable breath analysis.
Purpose of the Study:
- To identify potential artefacts affecting breath gas test reliability in practice.
- To evaluate the variability of breath gas sampling using proton transfer reaction-mass spectrometry (PTR-MS).
- To assess the impact of different collection timeframes on VOC measurement stability.
Main Methods:
- Instrumental variability of PTR-MS was validated using standard gas.
- Breath gas samples (mixed expiratory breath) were collected from volunteers over varying periods: 1 min, 1 h, and several days (15-70 days).
- Collected samples in Teflon bags were measured using PTR-MS.
Main Results:
- Samples collected within 1 min and 1 h exhibited low variability.
- Samples collected over longer periods (15-70 days) showed significant day-to-day variation in VOC concentrations.
- Inter-individual variability in methanol, acetone, and isoprene concentrations was higher than intra-individual variability over time.
Conclusions:
- Short-term breath gas sampling (1 min, 1 h) demonstrates low variability, suitable for diagnostic applications.
- Long-term storage or collection of breath samples (15-70 days) introduces significant variability, potentially due to room air contamination or other factors.
- High inter-individual variability suggests that personalized breath analysis or careful standardization is necessary for accurate biomarker interpretation.
