Can You Challenge a DUI Blood Test?

the truth about dui blood tests

Most people think that if law enforcement obtains a blood sample from you during a DUI investigation, you are stuck with whatever the result is. That’s not necessarily true.

Most people, including most defense attorneys, don’t know how police blood alcohol testing actually works. Did you know that DUI blood testing doesn’t actually test your blood at all? It’s true.

Today, I’ll help you understand the basics of DUI blood testing in Montana as well as many other states and why you need a premier attorney who knows what the results are and how to interpret the results.

gas chromatograph machineDUI Blood Testing Doesn’t Test Your Blood

What most people and most defense attorneys don’t know, is that “blood testing” in a DUI investigation in most states is a process called gas chromatography.

A machine called a gas chromatograph is used for this type of “blood testing.” Instead of just testing the blood for alcohol, the process is much more complicated.

How Gas Chromatography Works

Gas chromatography is a complicated process. I’ll summarize how it works.

  1. Your blood is transferred into a vial, but only about half of the vial is filled.
  2. The vial is then heated.
  3. Alcohol is volatile, which means it evaporates into air. So, the air that is the the empty half of the vial theoretically contains a proportionate amount of alcohol molecules to the blood.
  4. A needle is then inserted into this air space above the blood — not into the blood itself.
  5. This air (called “headspace”) is extracted through the needle, theoretically extracting the alcohol molecules in the air.
  6. This headspace gas sample has a known amount of other substance introduced into the sample for measurement purposes.
  7. The whole thing is then transferred via transfer gas into a different part of the machine called a “column.”
  8. Once there, a fire flame called an FID at the end of the column will actually burn up any contents of the sample, and the reaction with the flame and a detector is measured to calculate the amount of substances in a sample.
  9. This data is processed by a computer software program and the result is printed out on what is called a chromatogram.

Supposedly, this chromatogram is will show all substances contained within the headspace sample on a printed piece of paper called a chromatogram. Below is a chromatogram generated from a gas chromatograph:

chromatogram dui blood test

The vast majority of people, let alone attorneys, do not know how to accurately read a chromatogram, or know what it is telling you. This particular piece of evidence is the difference between winning a blood alcohol case and losing it due to not knowing the scientific process.

police car lights dui arrest

Photo: houstondwiPhotos mp

Interpreting DUI Blood Test Results

Most people don’t even know what they are looking at, let alone looking for, if they ever obtain a chromatogram. However, knowing what to look for and what not to look for is the difference between winning a case and losing a case.

Many defense attorneys will simply accept the result of your blood test and tell you there is no chance and plead you out. Only the most experienced and well trained DUI defense attorneys truly understand the specifics of this type of blood testing and how to overcome it.

If you have had a blood sample taken in a DUI investigation, ensuring your defense attorney understands DUI blood testing is the difference between having a chance at victory, and not having a chance at all.

Challenging DUI Blood Test Results

Experienced lawyers, like those at the Judnich Law Office, know what to look for when interpreting gas chromatography results. We also have access to the best and most experienced experts in the blood alcohol testing field, creating a team. Our defense team is one of the only in the state of Montana that are able to overcome blood alcohol results and point out the problems with them that can lead to dismissal of charges or exclusion of those tests.

We also know the exact protocols law enforcement officers are required to follow. We can spot small mistakes and inconsistencies that other lawyers miss, and we can use them to your advantage in court if necessary. Your defense team must know the science and problems associated with blood alcohol testing; if they don’t, then you have already lost.

Contact the Judnich Law Office

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Have you been charged with a DUI? Did law enforcement take a blood sample from you?

If you’re interested in learning more about the possibility of challenging blood test results in your DUI case, the Judnich Law Office can help you. We take every case seriously and it shows in our results.

Call the Judnich Law Office today at (406) 203-0913 in Missoula or (406) 602-8700 in Bozeman or contact us online to schedule your free, no-obligation consultation.