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Faulty breath tests: potential defenses against DWI charges

On Behalf of | Aug 9, 2024 | Criminal Defense |

Facing a DWI charge can be stressful, especially if it’s based on a breath test. These tests can sometimes give incorrect results due to various factors. It’s important to understand that there are ways to challenge these results and build a strong defense.

How breath tests work

Breath tests measure your blood alcohol concentration (BAC) to determine if you are legally impaired. The device estimates the amount of alcohol in your breath and converts it to an equivalent BAC. In Texas, a BAC of 0.08% or higher can result in a DWI charge. However, breath tests are not always perfect. 

Potential sources of error

Several things can cause a breath test to give a faulty reading. One common issue is the improper calibration of the testing device. If the device doesn’t undergo regular maintenance, it might produce inaccurate results. Additionally, certain medical conditions, like acid reflux or diabetes, can also affect breath test outcomes. Even the use of some mouthwashes or medications can lead to false positives and a DWI charge.

Environmental factors

Environmental factors can also impact breath test results. For instance, exposure to certain chemicals or fumes can alter readings. If you were around substances like paint or gasoline before taking the test, it could result in an inaccurate BAC level. Testing in high temperatures or windy conditions can also lead to skewed results.

Human error

The officer conducting the test must follow specific procedures to ensure accuracy. Mistakes in administering the test, such as not observing you for the required time before testing, can be grounds for questioning the results. Additionally, if the officer does not have the proper certification to conduct the test, this could be a significant point of contention.

Looking forward

Understanding the potential issues with breath tests can help you see the possibilities for defense against a DWI charge. These tests are not infallible, and various factors can affect their accuracy.