Law Office of Paul W. Hamilton

Are Blood And Other Chemical Tests Always Given In Marijuana DUI Cases?


In a large majority, over 90 percent, of cases where marijuana DUI impairment is suspected, there is usually a blood test because there is no other way to know whether marijuana is in the system. The only way to actually confirm that it’s active in the system is to have blood drawn. When that test comes back, it’s important to evaluate it, and in cases where it shows THC in the system, it’s important to determine what is actually in the blood. We’ve been very successful in challenging cases where the metabolite of marijuana, known as Carboxy, is shown in the system. This is notable because Carboxy is the non-psychoactive metabolite found in marijuana, which means it doesn’t cause impairment. You might have a blood test that comes back from a crime lab, which shows THC, yet in parentheses, it will say Carboxy versus Hydroxy.

Hydroxy is what impairs you; Carboxy is just the element that is processed from Hydroxy. So if Carboxy is what’s showing up in the blood test, then we can successfully argue that you weren’t under the influence of marijuana because it had already flushed through your system. So, in most cases, if there is a blood test, we can use it to our benefit. Some folks just get, frankly, a little overexcited when they see a positive for THC, but they don’t dig further to look and see if those were just metabolites or if those were the active marijuana elements in the blood. That can make a big difference in a DUI case.

Could Someone Face Additional Charges Besides A DUI Charge, Such As Possession Of Controlled Substance Or Paraphernalia?

Yes. Absolutely. In most of those cases, they are charged with the additional items. It’s not uncommon to see a DUI drug or DUI marijuana case with a charge of possession of marijuana, possession of a controlled substance or possession of pills not in the original container. That’s very common and happens a lot; in fact, if the case involves a Schedule 2 or Schedule 3 type of prescription drug, it can involve additional charges and additional penalties. In drug cases there are greater administrative restrictions on your license than in regular alcohol DUI cases

How Important Are The Results Of Blood Or Urine Tests In Marijuana DUI Cases? Are You Able To Use The Results In Protocol To Defend Clients?

The test results from blood or urine can be very important in marijuana cases. Urine is not as good of a test as blood is. Most of the times where we see a urine test in a DUI case, there is also a blood test done, which is important because it can show whether the active ingredient of THC, which is Hydroxy, is present in the individual’s blood. If that is present, it could show a level of impairment whereas if it’s Carboxy, which is the inactive metabolite of marijuana, then we can successfully argue to the prosecution that the individual wasn’t impaired by marijuana at the time they were stopped and charged with the offense.

Whether these tests are admissible in court is also a very good question. There are a number of protocols in place that must be complied with in order to introduce that blood test at trial. Interestingly, it’s easier to get a test that’s done by the hospital where the hospital is turning the blood into evidence than it is if the case is processed by the crime lab because there are strict protocols that are put into place to make sure that

  1. the person that was drawing the blood was qualified to do so and
  2. that the blood was not contaminated and was packaged properly. There have been a number of arguments that the tubes used to collect the blood were contaminated, the blood was improperly stored, and the testing procedures and protocols in the crime lab were not up-to-date.

There have been court cases where the crime lab in Georgia was found not to have properly processed blood samples or mixed up the blood samples. So there is a lot of room to attack the state analysis of the blood. I recently had a case in court where we just were relentless in attacking the state’s blood test and asked for material that the state didn’t want to provide. The judge compelled the state to provide it to us, which led the state to withdraw the blood test from evidence. So you can attack these cases; you just have to be very aggressive in doing so.

For more information on Chemical Tests For Marijuana DUI, a free initial consultation is your next best step. Get the information and legal answers you are seeking by calling (229) 207-0850 today.

Paul W. Hamilton, Esq.

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