How Breath Testing Works

Breath testing for alcohol content is the most common manner of testing for alcohol. In this context of testing a driver before and during his or her travels, it is the only way to test. Blood or urine testing is simply painful and/or impossible to perform in the quick, convenient and accurate way that ignition interlock breath testing can be done.

Breath testing for alcohol content is an indirect measure of testing for blood alcohol levels. However, it has been widely considered to be scientifically accurate, and, in California, the DUI laws are written to explicitly include both breath alcohol content and blood alcohol content as being legally acceptable.

Breath testing for alcohol concentration is typically performed on one of two types of machines: either an infrared device, or a fuel cell device.

Infrared devices are subject to many criticisms by forensic experts, criminal defense lawyers and DUI practitioners alike. These include interference from molecules that appear to be alcohol, but aren’t; radio frequency interference; discrepancies in sample chamber size; variations in body temperature; and more.

Fuel cell devices address many of these concerns. Breath alcohol testing with a fuel cell device does not require a sample chamber, or a beam of light to be passed through it. With a fuel cell, any amount of breath is passed over an electrical chip. When the sample is read by the device, it is electrochemically oxidized (meaning it is burned up) on the fuel cell itself. This produces an amount of electromagnetic current, which is then measured to equate to a given level of alcohol content.

Because of issues relating to portability, as well as specificity to alcohol without interference from other sources, most ignition interlock devices are of the fuel cell variety.

If you are in need of a California ignition interlock device, you are welcome to contact us anytime, 24 hours a day / 7 days a week, and one of our representatives would be happy to assist you.

Please call without delay: 1.800.880.3394