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DWI Question: Should I Retest My Blood?


This post is a common question from clients and attorneys.  You have been arrested for DWI, the police take your blood, and then your lawyer gets your blood results back and the piece of paper says your blood alcohol content is above a .08.   Well, if it’s written on a piece of paper that the government printed, it must be right, right? If your lawyer tells you that you must plead because of what a piece of paper says, then you need to fire your lawyer immediately.

There are many ways to fight a blood test.  This post is to argue against the most common way most people think you fight a blood test.  Retesting it.

I have never advised my client to get their blood retested for alcohol content, and I can’t imagine a set of circumstances where I would recommend retesting for alcohol.

Many clients, attorneys, and even some judges think the best way to fight a blood test is to have an independent lab retest your sample.  It makes sense to think that because you only had two to three drinks over a couple of hours that a different test would give a more accurate result.  It is very reasonable to presume there was a problem with the government’s machine and that an independent test would show your precise blood alcohol content.  Unfortunately, as evidenced by the fact that cops can forcibly draw your blood for a class B misdemeanor charge, common sense has little part in this process.

There are a number of reasons not to retest your blood for alcohol content.  The main reason is that the State is entitled to the result under most circumstances.  The only thing worse for your DWI case than having a blood test score over a .08 is to have TWO blood test scores over a .08.  The risk is not worth the reward.  Particularly when you consider the number of many reasons why you test would be over a .08.

Even if your lawyer is able to secure a Protective Order to keep the State from obtaining the retest (very unlikely), the likelihood of the retest score being lower than the original test is very remote.   Instead, if you believe that there is a large disparity between the test result and what you had to drink, then it is very possible that you have a (for lack of a better word) contaminated sample.  If your sample is contaminated, retesting it will not prove anything.  The question then becomes, how did the blood get contaminated?

Before you hire your DWI lawyer, you must ask him/her, how could my blood be contaminated? If they don’t have at least a couple of the following answers, you better hire someone who knows what they are doing.  Here is a short list, that is not exhaustive, of problems that could occur prior to your blood being tested that can greatly affect your blood test result:

  1. expired blood kit
  2. improperly stored blood kit (how hot does it get in the summer in the trunk of a cop car?)
  3. use of an alcohol based swab to prep for the draw
  4. incorrect swabbing technique
  5. wrong blood collection tube
  6. expired blood collection tube
  7. wrong sized needle
  8. length of time patient has tourniquet
  9. improper storage of blood
  10. improper mixture of blood and anticoagulant

This is just a sample of things that can go wrong before the blood is tested. A lawyer who handles these types of cases has to know these problems and has to be able to show they occurred.  How can your lawyer show the problems if he/she doesn’t even know what the problems are and why they pose a problem?  If any of these things occurred,  retesting your blood would not help you.  The problem has already contaminated a sample and you would be wasting your money.