How Does a Breath Test Work?

Breath tests were invented in 1954 by a Dr. Robert Borkenstein of the Indiana State Police. This was in response to the difficulty of taking a measurement of blood alcohol concentration in the field. Blood samples and urine tests are not the most field-friendly means of measurement, while a breathalyzer provides a less-invasive method. But, how does a breath test really work and is it an accurate measure of blood alcohol concentration?

How Alcohol Works

Alcohol is absorbed from the stomach, intestines, and even mouth and throat into the bloodstream. Upon absorption, it is not digested and also does not undergo a chemical change in the bloodstream.

Alcohol moves from your mouth to your lungs through the following:

• Alcohol is absorbed into the bloodstream.
• Alcohol moves through the membranes of the lung’s air sacs through the blood.
• Alcohol evaporates from the membranes into the air in the lungs.

The air in the lungs is called alveolar air. When this air is exhaled, the alcohol can be detected on a testing device. The more alcohol in your body – the more alcohol you exhale.

Types of Breath Tests and What They Do

All breath tests are similar in that they have a mouthpiece and a sample chamber. The mouthpiece is made up of a tube into which the suspect blows. The air is then sent through to the sample chamber.

Different types of breath tests include the following:

• Breathalyzer: This test produces a color change through a chemical reaction with the alcohol.
• Intoxilyzer: This test detects the presence of alcohol through infrared spectroscopy.
• Alcosensor III or IV: This test detects a chemical reaction of alcohol in a fuel cell.

How Accurate is a Breath Test?

The most accurate way to determine blood alcohol concentration is through a blood test. Breath tests can be used by the officer to help in determining whether he or she will arrest you; however, it is not admissible evidence against you in a courtroom.

Several factors may contribute to errors:

• False positives due to foreign substances containing alcohol (mouthwash, medicines, etc…)
• Improper calibration of a breathalyzer
• Glitches or bugs in breathalyzer software
• Error in operating the machine
• Failure to repeatedly administer tests
• False positives due to environmental factors (paint fumes, varnish, etc…)

Speak to a Fort Wayne OWI Attorney about Your Case!

Have you spoken to an attorney about your case? With legal help, you can better evaluate your circumstances and fight for the best possible outcome. At Arnold Terrill, P.C., our team can work with you to uphold your rights and defend you against whatever charges you face.