A breathalyzer (or breathalizer) is a non-evasive instrument used to measure an individual's Blood Alcohol Content (BAC) from their breath. Also known as an alcohol tester, most breathalyzers today are hand held devices for consumer and professional use.
A breathalyzer estimates BAC by measuring the amount of alcohol expelled by the lungs. As alcohol is consumed, the concentration in the blood increases. Lining the lungs, the membrane exhausts alcohol from the blood and into the longs. Breathalyzer sensors are able to detect the amount of alcohol and use that data to determine how much alcohol is in the blood.
When you hear about breathalyzers, it's usually in regards to four different types of devices:
- Evidential Breathalyzers: Desktop models used by law enforcement agencies. These devices can be used as evidence in most courts in the United States.
- Digital Hand Held Breathalyzers: Consumer and Professional grade breathalyzers are small devices that can accurate determine BAC. However most devices are only approved as screening devices and cannot be used as evidence against you. A positive reading can be used as probable cause to make an arrest.
- Disposable Single Use Breathalyzers: These devices use a patented chemical reaction to detect the presence of alcohol. Urine test strips are found to be the least effective breathalyzer available.
- Ignition interlock Breathalyzers: These devices are typically court ordered and installed between the ignition and the engine of a vehicle. A positive test result will lock the vehicle until it is inspected. This is the most costly breathalyzer and typically a consequence of a DUI.