"Electronic Noses" for the Detection of Volatile Organic Compounds in the Exhaled Air Disease-specific volatile organic compounds are produced mainly through changes in specific biochemical pathways in the body. Following their production by either human or bacterial cells, VOCs may be found in body fluids, including infected cells and/or their microenvironment, blood, breath, and saliva, among others. Thus, VOCs released from their origin can be directly detected from blood and the headspace of cells.