Dignity, Respect
& Justice

How do alcohol breath tests work, and what is their accuracy?

On Behalf of | Feb 10, 2023 | Drunk Driving |

Some Maryland residents end up pulled over by law enforcement officers on suspicion of drunk driving. Many in this situation submit to breath tests, but they have the right to question the results. This is what to know about these tests, their procedures, accuracy and results.

Understanding alcohol breath tests

Breath tests are designed to measure the amount of alcohol in a person’s system. When you drink, the alcohol is absorbed in your blood and is expelled when you breathe. Breath tests detect your blood alcohol concentration (BAC) in your blood by detecting it in your breath. When a person is intoxicated, it can cause their BAC to exceed the legal limit of 0.08%. When that happens, a police officer can arrest them for driving under the influence.

How breath tests work

A breath test must be properly calibrated in order to produce results. To use it, a person must blow into the test’s mouthpiece so that chemicals within a compartment can react with their breath. If alcohol is detected, the chemicals change color; that color goes from a reddish-orange to green.

Accuracy of breath tests

Unfortunately, breath tests are not always accurate. In some cases, the officer administering it makes a mistake such as improper calibration. False readings also often occur based on the person’s diet, products containing alcohol or even certain health conditions.

If you use an at-home alcohol breath test, your results are even more likely to be inaccurate. User error is more likely to produce incorrect results, which means a person might think they’re under the legal limit when they’re at or even over it. This could make for a disastrous situation if they plan to drive.

After a DUI arrest, it’s possible to challenge your breath test results. It might be the best defense in your case.