BREATH TEST SYSTEM

The invention relates to a breath test system that is unobtrusive in that it does not require a person subjected to the system to take any other action to breath. It comprises a sensor unit (5) configured to sense the presence or concentration of a volatile substance, present in air flowing through a predefined inlet area (4), and to generate a signal corresponding to the concentration of said substance. There is also provided an apparatus (2, 3) configured to detect the presence of a person at a position in the vicinity of said input area, and having means for registering said presence, and further configured to respond to said presence by delivering an output. This said apparatus includes a unit configured to call for immediate attention of said person, upon said registration of the presence of said person, and a unit configured to provide instructions to said person to direct an expiratory air flow towards said inlet area (4). An analyzer (10) for the determination of breath substance concentration of said person is also provided, the determination being based on said signal corresponding to the substance concentration.