If police officers pull you over because they suspect you of driving drunk, you probably already know that you can expect them to test you with a portable Breathalyzer. Many people make the mistake of thinking that a positive result makes the case against them a slam dunk. They give up and do not even bother fighting their DUI charges.
However, nothing could be further from the truth. While a positive result can be enough to allow the officers to file DUI charges, it will not by itself support a conviction. This is because Breathalyzer results can vary and may generate false positives due to a number of causes.
How it works
The Breathalyzer operates by measuring the percentage of alcohol in your breath. Theoretically, if you have alcohol in your bloodstream, your blood delivers it to your lungs, where a certain percentage escapes into the air you exhale. The problem arises when the alcohol in your breath comes from sources other than your lungs. Alcohol-based mouthwashes, as well as mints containing substances such as sorbitol and menthol, can generate a positive result.
Another common problem arises if you had even a slight amount of alcohol shortly before the test, as the alcohol will linger in your mouth and artificially raise the measured level. People with dentures or implants may retain little pools of alcohol inside their mouths, also causing an appearance of a high blood alcohol level.
Chemicals in the environment
People who work in environments with high levels of acetone, such as house painters or salon workers, can absorb acetone from the outside. This is another factor that can affect a breath test.
Health conditions can induce an unusually high concentration of acetone or ketone in the breath, which can also elevate breath BAC readings. Uncontrolled diabetes is one such condition. If you are on a very low-carb, ketosis-inducing diet, your ketones can also create a false positive.
If you are facing DUI charges because of a false positive on a breath test, a qualified attorney can help you fight a conviction. Experienced defense lawyers know how the tests work and how to challenge prosecutors' use of unreliable evidence.