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2 factors that influence the accuracy of chemical breath tests

On Behalf of | Aug 9, 2023 | DUI/DWI |

The state needs evidence to successfully prosecute someone for impaired driving. With the exception of video footage of someone driving erratically or failing a field sobriety test, chemical test results are probably the most compelling evidence that police officers can gather to establish someone’s likely impairment at the wheel.

Many driving under the influence (DUI) cases largely rely on chemical breath test results to convince a judge or jury beyond a reasonable doubt that someone has broken the law. Some people even plead guilty because they assume they can’t defend against charges given damning test results. However, those test results may not be as accurate as people often assume. In fact, there are multiple reasons why breath test results may not be an accurate reflection of how much someone has had to drink.

Health and dietary factors

The physical condition of the individual performing the test can potentially trigger a false positive result. For example, if someone follows a keto diet, their attempts to burn fat might result in their body producing acetone while they are in a state of ketoacidosis. The acetone in their breath could then result in a false positive result on a breath test. There are several different medications and even health conditions, like undiagnosed diabetes, that can also trigger false positive results. Even using mouthwash right before the traffic stop could compromise the accuracy of the test results.

The maintenance of the device

A breath testing device has to perform very precise chemical measurements. Therefore, the maintenance of the device itself can have a major impact on the accuracy of test results. Going too long without calibrating the device, failing to install software updates and other maintenance issues could easily result in inaccurate breath test results that make it look as though someone was over the legal limit when they actually were not.

Especially in cases where the only evidence affirming someone’s theoretical impairment at the wheel is a breath test, challenging the accuracy of the device or the results it has produced could be a viable defense strategy. Learning more about how the state proves drunk driving allegations and the limits of the most common forms of evidence may help people hoping to fight back against impaired driving allegations.