The diagnosis of invasive pulmonary aspergillosis (IPA) bears grave implications for the prognosis and treatment plan of the immunosuppressed patient. Thus far, such diagnosis in the immunosuppressed patient, such as patients with acute myeloid leukemia (AML), relied heavily on chest computed tomography (CT) and bronchoalveolar lavage (BAL), an invasive approach bearing many caveats. Volatile organic compounds (VOC) are compounds that could be detected in exhaled air, and have shown some potential in the non-invasive diagnosis of various conditions, including IPA. In this prospective longitudinal study we aim to compare the VOC profiles of patients diagnosed with AML (baseline) to the profile of the same patient diagnosed with IPA later on, and to the post recovery profile in the same patient. This approach should resolve many of the issues plaguing prior attempts at VOC based IPA diagnosis, mainly the lack of properly designed controls. Samples will be collected from consenting patients using Tedlar bags, and analyzed using thermal desorption gas chromatography mass spectrometry (TD-GC-MS). VOCs detected will be digitally analyzed to construct different classification models, with predictive performances compared to the clinical diagnosis using the accepted methods will be assessed by binary logistic regression.