One DWI, Two Very Different Breath Tests

“The Officer Had Me Blow Twice in My DWI Case”

Frequently during new client consultations for DWI cases I hear, “They had me blow twice.” Usually this means the police officer administered a preliminary breath test at the scene, prior to placing my client under arrest, then administered an evidentiary breath tests once back at the station. There are times when no preliminary breath test is given, and other times when the evidentiary breath test takes place at the scene after the arrest. However, during most DWI investigations a preliminary breath test is given after the field sobriety tests, but prior arrest, and the evidentiary breath test is administered about 30 minutes after the person arrives at the police station.

What is the Difference Between the Two Breath Tests?

Preliminary Breath Tests – The preliminary breath test is a small, handheld device that police officers generally use at the scene of a DWI investigation. The test does result in a blood alcohol content read out, but these preliminary, or portable, breath tests do not have the same safeguards or standards that the evidentiary breath tests require. For example, the preliminary breath tests do not have to be calibrated … ever … under Missouri law. There is also no way to detect mouth alcohol, which can skew the results of the test dramatically. Due to these shortcomings, the results of a preliminary breath test can only be used in court to show whether there was a presence of alcohol on a person’s breath. The actual blood alcohol content cannot be entered into evidence in court, unless it is below the legal.

Evidentiary Breath Tests – The evidentiary breath test is generally administered at the station, but there is a new evidentiary breath test machine that is portable. Either way, the evidentiary breath test must be administered after the arrest. The term “evidentiary breath test” is used to describe a breath test that can be used as evidence of a person’s blood alcohol content in court. These machines are significantly better than the preliminary breath tests, but still have many shortcomings themselves. Here are some of the problems with Missouri breath tests.

If you have been asked to take a breath test there are many possible Breath Test Defenses available. Please contact The Law Office of Jason A. Korner to discuss your rights and options when facing breath test evidence.

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