Blood And Breath: What To Expect With Sobriety Testing

When you end up behind bars and charged with driving under the influence (DUI), your case depends on evidence. The state must be ready to show that you were intoxicated at the time of the roadside stop, and the blood and breath evidence are two strong ways this is accomplished. Read on to learn more about this form of DUI evidence and how the results can be skewed and inaccurate.

Breathalyzer Results

Law enforcement will often administer a test called a breathalyzer at the scene. This is a variation on the more accurate and bulky machine that awaits those arrested back at the police station. The portable breathalyzer tests the level of alcohol metabolized in the drinker's body by measuring the breath. This small device is calibrated and then the suspect is asked to blow into it. The resulting number is supposed to provide the blood alcohol concentration (BAC) of the suspect and is expressed in a percentage number. In all states, those who test at .08% or more are considered above the legal limit.

While the non-portable version might be a bit more accurate than the roadside test, it too suffers from some of the same issues. All of those issues are sure to be targeted and addressed by your criminal defense attorney when forming your case and when considering plea deals. Using the exhaled breath to determine intoxication has several problems and all of them revolve around the personal characteristics and habits of the person undergoing the testing. Here are just a few things that can influence the results of a breathalyzer when testing BAC:

  • The use of mouthwashes and breath mints prior to testing.
  • A burp or belch prior to testing.
  • Acid reflux.
  • Vomiting right before testing.
  • Use of toothache pain relievers.

And more.

Blood Test Results

Where breathalyzer results can be inaccurate, blood test results are a step above. If the state can present evidence of a proper blood draw and a resulting BAC level that is above the limit, you may have more of a challenge to fight the DUI charge. Blood draws can only be performed with a warrant and they must be done correctly for the result to be admissible. Only those specifically-trained to draw blood may perform this test and the blood sample must be handled in a certain manner to preserve the integrity of it. Once drawn, the blood has to be kept at a certain temperature and it must be tested for the presence of alcohol within a relatively short period of time. Blood that is tested too long after the draw can begin to coagulate and that can lead to false-positive test results. The way the blood sample is handled is known as the chain of evidence and this process should be examined closely for problems. Any impropriety should be addressed in your defense.

An examination of the breathalyzer and blood results are just the beginning of a good DUI defense. Speak to a DUI attorney to find out more.