When The Going Gets Tough,

We'll Be There With You

What can cause a false reading in a breath test?

On Behalf of | Jan 8, 2024 | Blog, Criminal Law

Law enforcement agents often use breath tests to determine the blood-alcohol concentration of drivers they suspect of operating a vehicle under the influence. However, these tests can sometimes give false readings and lead to unjust convictions.

Anyone facing an OUI charge should understand the reasons behind such inaccuracies as they prepare their case.

Human error and faulty equipment

Human error can play a significant role in the accuracy of breath tests. For example, the arresting officer may not follow the correct procedure when administering the test, such as not giving the driver the appropriate waiting time.

Breath test machines can also give inaccurate readings if the users do not calibrate them appropriately or carry out regular maintenance. A machine can also suffer from a mechanical or electrical fault, leading to a false reading.

Tellingly, the Massachusetts Supreme Judicial Court has found evidence of misconduct involving a coverup of breath test machine problems. The ruling opened the door for approximately 27,000 people to request a dismissal of drunk driving charges.

Mouth alcohol levels and medical conditions

Mouth alcohol refers to vapors in the mouth that could present as alcohol in the lungs. These vapors can arise from the digestion of substances that contain alcohol, such as mouthwash, breath fresheners and cough syrups, as well as the regurgitation of stomach contents.

Additionally, certain medical conditions can affect the accuracy of breath tests. For example, people with acid reflux or other gastrointestinal conditions that cause chronic regurgitation of stomach contents can release mouth alcohol into the breath. Similarly, people with diabetes and liver diseases can produce acetone, which the breath test can pick up and give false readings.

Breath test equipment is not perfect and can render an incorrect result. Understanding the causes of false readings can help a person find useful evidence for a just ruling.