When law enforcement and court officials are investigating and prosecuting drunk driving offenses, they often rely heavily on breath and blood tests as evidence of the defendant's alleged wrongdoing. But as with all technology, these tests can make mistakes, and so their results are never 100 percent reliable.

However, anyone who attempts to claim that their DWI breath test results are wrong is often portrayed as a liar or someone who is grasping at straws to avoid a drunk driving condition. Of course, that may sometimes be true, but to universally declare that someone who challenges a Breathalyzer test is lying is unfair to defendants who legitimately claim that their breath test was inaccurate.

For example, defendants who suffer from acid reflux may have a valid claim that their breath test did not accurately depict their blood alcohol content. Specifically, many people in St. Louis and throughout the country have successfully argued that gastroesophageal reflux disease, or GERD, elevated their blood alcohol reading and that they were not actually driving drunk.

GERD often results in the regurgitation of semi-digested or undigested acids containing alcohol. Generally, a breath test measures the amount of alcohol in deep lung tissue and correlates that to the amount of alcohol in the blood. But when those alcohol-containing acids enter the mouth or throat, the breath test may measure them instead of the lung air, causing a falsely high reading.

If a defendant successfully gets their breath test results thrown out, the prosecuting attorney will have to prove beyond a reasonable doubt that the defendant was driving drunk using other evidence such as field sobriety tests and officer testimony.

Source: The News and Observer, "Apex council member fights DWI," Anne Blythe, Feb. 4, 2012