Abstract: Disclosed is a method of determining a condition of a subject based on Volatile Organic Compounds (VOCs) in a gaseous phase, originating from the subject. The method may include: receiving from one or more sensors a set of sensor signals in response to exposing the one or more sensors to a sample of the VOCs; extracting one or more feature values from the set of sensor signals; receiving a classification model, trained to classify samples of VOCs based on the one or more extracted feature values correlated to one or more condition of the subject; associating the one or more extracted features received from the set of sensor signals with one or more classes of the classification model; and determining the condition of the subject based on the association.