You Gave a Breath Test. Now what?

Defenses to Breath Tests for Blood Alcohol Content (BAC)

Whether you were asked to blow in the roadside handheld gadget or into a larger more accurate machine at the police station, the truth remains that BAC breath test machines are not perfect. They have to be calibrated and they have to be properly administered by a qualified person. I will provide a few of the potential defenses that may be available to you.

Breath Machines Require Maintenance to Work Properly

Breath machines are by no means infallible. They are gadgets that require upkeep and maintenance. In Missouri, they have to be checked every 35 days. If the machine is not working properly, then it has to be calibrated.

Sometimes the records show the machine was not functioning properly, or was reading too high (or too low). There have to be records of repairs, calibration, accuracy checks, maintenance, etc. Sometimes records cannot be furnished or are missing. It is the prosecution’s burden to prove the machine was working properly. If the machine was not working properly, a good DWI defense attorney will argue that the evidence is not reliable and therefore not relevant and that it should be excluded. If the Judge allows the evidence to be introduced, the defense attorney will argue that the evidence should be given little or no weight or importance due to the issues surrounding the machine.

Accuracy Checks and Calibrations Have to be Done Properly

In order to determine whether a machine is working properly, a certain methodology has to be followed. If that methodology is not properly followed, then that casts doubt on the reliability of the result. When a result is not reliable, then it is not relevant, and evidence that is not relevant is not admissible.

For example, to ensure reliability, accuracy checks require the simulator solution to be heated to a specified 34 degrees centigrade. This brings into question whether the thermometer was working properly, or ever checked.

Or when dry gas standard is used to calibrate the machine and to obtain proper results, whether the barometric pressure measuring device of the machine was checked as well.

If the prosecution can’t show that a BAC breath test machine was inspected correctly, a good DWI defense attorney will raise this to the Court and try to use it to your advantage.

Who is Administering the Breath Test and How is it Being Administered?

The person who administers the breath test has to have proper qualifications. This is not done by a lay person, but by one who has received proper training.

Along the same lines, even if the person is properly qualified, did that person properly administer the test by following specific protocols? Such protocols include following the machine’s manual and also additional regulations set by the State of Missouri.

If there are any problems or questionable evidence with regard to who administered your breath test — and how — it’s your defense attorney’s job to investigate and use this to your advantage.

The 15 Minute Observation Rule

Before one is asked to blow into a machine to measure their blood alcohol content, there has to be a 15 minute observation period. The 15 minute observation period is put in place to ensure reliability of the results.

There have to be 15 minutes of direct observation. During these 15 minutes, the person who is going to be tested must not eat, drink, smoke, vomit, or regurgitate (burp any contents into your mouth). Any one of those can increase the reading of the machine.

Often officers who are supposed to observe a person for 15 minutes straight do not do it properly. What if that person has a severe case of indigestion and brings up the content of his stomach up to his mouth and contaminates his mouth with alcohol? If sufficient time has not passed to allow the mouth contamination to dissipate, that can very well result in a higher reading.

Your defense attorney should review the evidence, reports, audio/video recordings, and also ask you detailed questions about whether the observation rule was followed in your case. If not, you may have a defense to the test results.

Additional Potential Defenses for Breath Tests

There are many other areas where a breath test can be challenged.

Partition ratios of blood to breath, lack of slope detector of the breath machine, margins of error, dental work, tongue studs and mouth jewelry, GERD, diabetes, lung conditions, machines that measures substances other than alcohol (ethanol) that lead to higher readings, whether the alcohol in the system reached equilibrium, breath machines that may have been subject to radio frequency interference, etc.

The above list is not exhaustive. Depending on the facts of the case other defenses may be available.

The only way to determine whether any potential defense exists is to actually roll up the sleeves and get to work on finding them.

And that is exactly what I will do.

(816) 221-3691