Fig. 7.

Overview of the processes involved in breath testing: exhaled breath is a complex mixture of gases, water vapor, and thousands of VOCs in which only a small number of specific VOCs and gases comprise the clinically significant breath print. In order to perform the breath test, a sample is prepared from the complex mixture of exhaled breath by “trapping” the breath components on a sorbent material (followed by thermal desorption for their release), within a collection container (for example, a bag, vial, or canister), a dehumidification unit, or a channeling unit for direct delivery. The sample is then delivered to a measurement chamber through a simple delivery channel or a microfluidic system. In the measurement chamber, the breath components interact with the recognition element of the NMVS, inducing a measurable change (that is, electrical or optical) in the transducer that is translated into an output signal. Data analysis is then performed on the output signals in order to make the clinical prediction of the breath test. Reconstructed from ref. 138.