When are breath tests inaccurate?

On Behalf of | Jun 6, 2024 | Criminal Defense

Breath tests, often used to measure blood alcohol content, or BAC, play a big role in determining if someone is driving under the influence of alcohol.

Despite their importance, breath tests can be inaccurate. Several factors influence the reliability of these tests.

Medical problems

Certain medical conditions can cause inaccurate breath test results. People with diabetes may have high levels of acetone in their breath. Breath tests could mistake acetone for alcohol, resulting in a falsely high BAC reading.

Gastroesophageal reflux disease can also affect results. This health issue causes stomach acid to travel up the esophagus. This could increase the alcohol concentration in the mouth and lead to an inaccurately high reading.

Mouth alcohol residue

Mouth alcohol may cause breath tests to be inaccurate. Residual alcohol from recent drinks, mouthwash or medications containing alcohol can remain in the mouth.

Some residual alcohol could lead to a higher BAC reading than the actual amount of alcohol in the bloodstream. Officers need to wait 15 to 20 minutes before testing to make sure any leftover alcohol goes away. However, they may skip this step, leading to inaccuracies.

Environmental influences

Environmental factors also impact breath test accuracy. The presence of certain chemicals in the environment can interfere with breath test readings.

Some of these include paint fumes, gasoline or cleaning products. These substances contain compounds that breath tests may confuse with alcohol, resulting in a false positive.

Poor device maintenance

Breath tests require regular maintenance and calibration to function accurately. If officers do not calibrate or maintain a device, it can lead to incorrect readings. Regular checks ensure that the breath test measures BAC near the legal limit accurately and consistently.

Understanding these influences is important for interpreting breath test results in the correct context. Accurate breath tests help ensure that BAC readings and any criminal charges are fair.

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