Dynamic Changes in Exhaled Breath Glucose by Condensate Collection During Oral Glucose Tolerance Testing in Healthy Adults

Purpose: Invasive blood glucose monitoring is associated with pain and suboptimal patient adherence, creating a need for non-invasive alternatives. In this study, we investigated the dynamic relationship between glucose levels in exhaled breath and blood during an oral glucose tolerance test (OGTT) in healthy adults, to assess the feasibility of using exhaled breath glucose as a non-invasive marker for glycemic monitoring. Methods: Twenty healthy volunteers (12 males, 8 females; mean age 23.1 ± 2.4 years) underwent a standardized OGTT test. Exhaled breath condensate (EBC) and blood samples were collected simultaneously at fasting (0h) and at 0.5h, 1h, 2h, and 3h post-glucose load. EBC glucose concentration was measured using ion chromatography. The temporal profiles of both parameters were analyzed, and the correlation between the rate of change in exhaled breath glucose and blood glucose at each time point was assessed using Pearson or Spearman correlation test. Results: > 0.05). Conclusion: Exhaled breath glucose levels dynamically track blood glucose changes during the early postprandial phase in healthy adults, demonstrating strong concordance during periods of rapid glycemic excursion. These findings support the feasibility of EBC as a non-invasive tool for monitoring glycemic trends. Further validation in larger cohorts and diabetic patients is required to establish its clinical utility.