Differences in exhaled gas profiles between patients with type 2 diabetes and healthy controls

Recent advances in analytical technology allow the detection of several hundred volatile organic compounds (VOCs) in human exhaled air, many of which reflect unidentified endogenous pathways. This study was performed to determine whether a breath gas analysis using proton transfer reaction-mass spectrometry (PTR-MS) could serve as a noninvasive method to distinguish between patients with type 2 diabetes mellitus and healthy controls. Breath and room air samples were measured from 21 patients with insulin-treated type 2 diabetes and 26 healthy controls. VOCs in the mass range of 20-200 atomic mass units were analyzed using PTR-MS. We identified eight masses characteristic of endogenous VOCs that showed significant differences in the gas profiles of patients with type 2 diabetes and healthy control subjects. Using these VOCs for linear discriminant analysis, the sensitivity and specificity were found to be 90% and 92%, respectively. These results suggest that it is possible to separate patients with diabetes mellitus type 2 from healthy controls by multivariate analysis of exhaled endogenous VOCs. This is a first step towards the development of a noninvasive test using breath gas of at-risk persons and making it an attractive option for large-scale testing of at-risk populations. However, the establishment of exhaled volatiles as metabolic markers requires additional confirmatory investigations.