Influence of condensing equipment and temperature on exhaled breath condensate pH, total protein and leukotriene concentrations

SummaryBackgroundExhaled breath condensate analysis is an attractive but still not fully standardised method for investigating airway pathology. Adherence of biomarkers to various condensing surfaces and changes in condensing temperature has been considered to be responsible for the variability of the results. Our aims were to compare the efficacy of different types of condensers and to test the influence of condensing temperature on condensate composition.MethodsBreath condensates from 12 healthy persons were collected in two settings: (1) by using three condensers of different type (EcoScreen, R-Tube, Anacon) and (2) by using R-Tube condenser either cooled to −20 or −70 °C. Condensate pH at standardised CO2 level was determined; protein content was measured by the Bradford method and leukotrienes by EIA.ResultsBreath condensates collected using EcoScreen were more alkaline (6.45±0.20 vs. 6.19±0.23, p<0.05 and 6.10±0.26, p<0.001) and contained more protein (3.89±2.03 vs. 2.65±1.98, n.s. and 1.88±1.99 μg/ml, p<0.004) as compared to the other devices. Only parameters obtained with R-Tube and Anacon correlated. Condensing temperature affected condensate pH (5.99±0.20 at −20 °C and 5.82±0.07 at −70 °C, p<0.05) but not protein content. Leukotriene B4 was not found in any sample and cysteinyl-leukotriene was not found in condensates collected with R-Tube or Anacon.ConclusionCondenser type influences sample pH, total protein content and cysteinyl-leukotriene concentration. Condensing temperature influences condensate pH but not total protein content. These results suggest that adherence of the biomarkers to condenser surface and condensing temperature may play a role but does not fully explain the variability of EBC biomarker levels.