The effect of temperature on exhaled breath condensate collection

• Published in: Journal of breath research 2012-09, Vol.6 (3), p.036002-036002
• Main Authors: Vyas, Aditya, Zhang, Qi, Gunaratne, Shyamini, Lee, Wei, Lin, Jiun-Lih, Lin, Jiun-Shiang, Warwick, Geoffrey, Thomas, Paul S
• Format: Article
• Language: English
• Subjects: Biomarkers; Breath Tests - methods; Cross-Over Studies; Exhalation; Female; Humans; Hydrogen Peroxide - analysis; Hydrogen-Ion Concentration; Male; Nitrites - analysis; Proteins - analysis; Temperature
• ISSN: 1752-7155; 1752-7163
• DOI: 10.1088/1752-7155/6/3/036002

Exhaled breath condensate (EBC) collection is an innovative method of non-invasively sampling the lung, and can detect a variety of volatile and non-volatile biomarkers, but the disadvantage is the small volume of sample collected. It was hypothesized that a collection system at a lower temperature would increase the volume collected, but may alter the relative concentration of the biomarkers of interest. EBC was collected in a cross-over study using a custom-made collection system, cooled using either wet (4 °C) or dry ice (−20 °C) in randomized order in normal non-smoking volunteers. The volume of the EBC collected per unit time was determined as were conductivity, the concentrations and total amount of protein, hydrogen peroxide, and nitrite nitrate concentrations. Dry ice was associated with a 79% greater volume of EBC than the wet ice (1387 ± 612 µL; 773 ± 448 µL respectively, p < 0.0001). Conductivity was influenced by the temperature of collection (18.78 ± 6.71 µS cm−1 for wet ice and 15.32 ± 6.28 µS cm−1 for dry ice, p = 0.02) as was hydrogen peroxide (1.34 ± 0.88 µg mL−1 for wet ice and 0.68 ± 0.32 µg mL−1 for dry ice, p = 0.009) while the concentrations and total values for protein and nitrate nitrite were not significantly different (p > 0.05). This pilot study suggests that lower collection temperatures facilitate the collection of a larger sample volume. This larger volume is not simply more dilute, with increased water content, nor is there a simple correction factor that can be applied to the EBC biomarkers to correct for the different methods.