People will sometimes act as if the results of a breath test are ironclad. Field sobriety tests may be a bit more subjective. But if a breath test measures someone’s blood alcohol concentration (BAC) and says that they are at or above the legal limit, people think of that as solid proof.
But is it? It’s not nearly as simple as that. Breath tests can certainly be wrong, and there are a variety of reasons why.
Maintenance and calibration
In some cases, the tests have not been calibrated properly, or they may have not been maintained on a set schedule. Even labs can have maintenance issues when analyzing the results. Once these results are called into question, they may not hold up in court
For example, one officer made a calibration mistake and the department administered numerous tests using that calibration. In the end, over 18,000 breath tests were invalidated due to this error.
Another thing to consider is that a breath test can be influenced by other factors. For instance, someone will have a higher reading if they still have alcohol in their mouth. There are cases where people may burp during a test and give a false reading, or where they may have used mouthwash containing alcohol just before taking the test. These issues could lead to much higher BAC readings than if the concentration in their blood was actually measured on its own.
These examples show that breath tests should not be treated as if they are never wrong. Mistakes are often made, and those who are facing legal charges need to know exactly what options they have.