Why might breath test results be wrong?

On Behalf of | Sep 30, 2023 | Criminal Defense |

Breath tests that are used to measure blood alcohol concentration (BAC) can sometimes produce inaccurate results. This is problematic because these tests are often used in court as evidence of impairment when a driver was allegedly operating a vehicle with a BAC over the legal limit.

It’s essential to understand potential sources of error when assessing whether any particular test conclusions are truly accurate or not. These are some common reasons why breath test results could be wrong.

Calibration and maintenance issues

Breathalyzer devices require regular calibration and maintenance to ensure accuracy. If a device is not properly maintained or calibrated, it can produce inaccurate readings. Usually, police departments should have a set calibration and maintenance schedule that they stick to, ensuring that all devices are always ready to take accurate readings. Ignoring this schedule quickly means that test results could be significantly off the mark.

Contamination and mouth alcohol

If the breathalyzer mouthpiece or other components are contaminated with substances like food, drink or cleaning chemicals, it can affect the accuracy of the test. Likewise, residual alcohol in the mouth – perhaps from recent consumption or regurgitation – can lead to artificially high BAC readings. It’s essential for individuals to wait for a period of time after consuming alcohol before taking a breath test to avoid this issue.

Human error

An officer administering a test needs to be properly trained, and they need to follow correct procedures. Errors by the operator, such as not ensuring a proper seal or not observing the waiting period, can lead to inaccurate results. Human error is one of the most common reasons for inaccurate readings, and it’s important to remember that the test is only accurate when an officer uses it correctly. Even small errors can be enough to skew results and impact the outcome of a case.

Medications and substances

Some medications and substances, including over-the-counter cough syrups and mouthwashes, can contain alcohol or other compounds that might register as alcohol on a breath test.

To minimize the risk of inaccurate breath test results, it’s important for the police to use well-maintained and calibrated devices, follow proper testing procedures and consider potential sources of error when interpreting the results. Those who are facing charges need to know what legal defense options they have, especially if they suspect that the results are inaccurate.