Highlighting the margin of error for breath testing devices

| Jan 31, 2021 | DUI |

Given how closely most people in Minnesota associate breath testing devices with drunk driving charges, you might believe their results to be infallible (why else would law enforcement authorities rely on them to justify a DUI arrest?). Yet, like many, you may question how a breath test offers an indication of the alcohol content of your blood.

Many clients come to us here at the Bauer Law Office with that very question. Knowing the answer requires that you understand how alcohol gets from your blood to your breath. A comprehension of this process may even help you to call into question the results of a breath test officials may attempt to use against you.

The pathway alcohol takes through your body

When you consume alcohol, the exact form of alcohol you take in is ethanol. This is a water-soluble compound, which allows it to pass through the linings of the organs of your gastrointestinal tract and enter into your bloodstream. Your veins then carry the ethanol throughout your body. In the lungs, some of that ethanol vaporizes into a gas when it comes in contact with oxygen. You then expel that gaseous oxygen when you breathe. The level of alcohol on your breath remains in equilibrium with that in your blood.

The mechanics of breath testing devices

According to the Alcohol Pharmacology Education Partnership, breath testing devices assume that the blood-to-breath ratio that represents that equilibrium to be 2100:1. However, in reality, your actual blood-to-breath ratio may vary between 1500:1 and 3000:1. Factors such as your age, gender and genetic makeup influence that number. Whatever the reason, that wide range may explain why many experts estimate that breath testing devices have a margin of error as high as 50%.

You can find more information on challenging DUI charges throughout our site.