Are breath tests always accurate?

| Feb 2, 2017 |

The breath test is among the most common tools police officers use to bolster DUI charges. If you are stopped on suspicion of drunk driving, you will most likely be asked to breathe into a machine that measures your blood alcohol level. A positive reading will serve as evidence of impaired driving and can result in serious consequences if not challenged.

Although makers of breathalyzers like to claim that their machines are highly accurate, in reality, there are many factors that can result in a falsely high alcohol level reading. If any of these factors are present, the validity of the breath test results can and should be called into question.

Incorrect operation

One factor that affects the operation of a breathalyzer (and any other machine) is human error. Correct operation is a requirement for getting an accurate result. This includes regularly testing and calibrating the breathalyzer – a step that busy officers sometimes omit. Operators must also use a new mouthpiece for each test to avoid possible contamination from previous tests. Another procedural safeguard that officers sometimes ignore is the required wait time of 15 minutes. This wait is to ensure that mouth alcohol will not affect readings.

Acetone-generating health conditions

Health conditions and medications may also create a falsely positive read-out. In particular, any condition that produces high levels of acetone in your body can cause the breathalyzer to register the presence of alcohol even if you did not drink before your test. A common example is diabetes, especially if it is not well-controlled. Healthy people who are fasting or on a low-carb diet may also exhibit elevated acetone. Conditions like acid reflux can cause artificially high alcohol readings as undigested alcohol in the flow of stomach contents can affect your breath.

Acetone in the environment

Other sources of acetone can include your habitual environment or residue on your clothing or in your vehicle. Substances such as many types of paint, nail polish and industrial cleaners may contain a high level of acetone. If you have substantial exposure to acetone, it can affect your breath test results.

Retained mouth alcohol

The breath test measures the percentage of alcohol in your breath from your lungs. The idea is that your lungs absorb a particular percentage of alcohol from your bloodstream. However, if you have alcohol in your mouth, the readings will skyrocket, presenting an inaccurately high result. Dentures, braces and bridges present rough surfaces that tend to retain pockets of alcohol. This can be the case even if the alcohol in questions comes from a source like mouthwash rather than an intoxicating beverage.

Failing the breath test does not mean an inevitable DUI conviction. Consult an experienced attorney near you to find out about possible defense strategies. You may have more options than you think.