Abstract: In a mass spectrometry method, a deuterium-resolved mass spectrum of a gas sample comprising volatile metabolites that have been excreted from a human or animal subject (50) after ingestion of deuterated water is determined. The deuterium-resolved mass spectrum to determine a presence or amount of at least one deuterated metabolite. Also disclosed is a corresponding mass spectrometry system.

Abstract: A computer-implemented method for processing mass spectrometry data from breath gas including receiving a time-dependent ion profile originating from a spectrometer data sample (D1,D2), the spectrometer data sample (D1,D2) having been recorded during at least one exhalation from a subject (1); each time-dependent ion profile being associated with one mass-to-charge ratio value and including a signal strength for the one mass-to-charge ratio value measured over a time duration. The method further includes receiving a time-dependent breath profile, the time-dependent breath profile having been recorded during the at least one exhalation over the time duration, and a temporal correlation step (200), the temporal correlation step (200) including: determining a degree of temporal correlation between the at least one time-dependent ion profile and the time-dependent breath profile, and classifying the at least one time-dependent ion profile based on the degree of temporal correlation.

Abstract: The present invention relates to an ex vivo method and means for determining the risk estimate of side effects of a drug and/or probability estimate of drug response in a subject, the method comprising collecting the mass spectra of substances present in the exhaled breath and analyzing the mass spectra using a previously trained mathematical model. The instant methods and means are particularly useful in therapeutic drug monitoring, determining the risk estimate of side effects of a drug, determining the probability estimate of drug response in the subject, and determination of subject compliance.