Experienced DWI Defense Serving North Texas.

Can You Challenge DWI Blood Test Results?

If an officer arrests you on suspicion of driving while intoxicated, they may subject you to a chemical test to determine how much alcohol was in your system. In Texas, a blood alcohol concentration (BAC) of .08 while operating a vehicle is illegal. Thus, if the results reveal that you were at or above the limit, you will be charged with a DWI.

Several methods are available to allow law enforcement officials to measure your BAC, including breath and blood tests. Blood tests are considered the most reliable, as they directly measure the percentage of alcohol in your blood. However, just because they are more reliable does not mean they're infallible.

Various factors can affect the test and produce inaccurate BAC measurements, which means that you could be charged with (and possibly convicted of) a DWI because of an error in the testing process. This is why it's necessary to have a skilled attorney review your case, identify any errors that may have affected your results, and challenge the accuracy of your blood alcohol test.

A few of the ways a blood test may be challenged include, but are not limited to:

  • Technological errors: If you've used any technology (i.e., a phone, laptop, car), you might have encountered some error that prevented the device from working right. Just as your devices, a blood-testing machine is a type of technology that can, at times, malfunction. Improper maintenance, software errors, or incorrect handling can cause the device to act up. Unfortunately, such flaws are not harmless; they can lead to a criminal conviction even when the person accused did not break the law. An attorney will know what to look for and what questions to ask about the blood testing machines. If, during the discovery period, an error is revealed, it's possible to attack the results of a blood test.
  • Procedural flaws: To get the most accurate results, any testing must follow specific procedures. When it comes to a DWI blood test, everyone who handles any part of the process must do so according to established protocols. The person who takes your blood must ensure that the puncture site is prepped correctly. The arresting officer must ensure the blood sample is stored properly before it's analyzed. If anybody misses a step or mishandles the specimen, the results of the analysis may be inaccurate. For instance, if the blood isn't refrigerated after the nurse, doctor, phlebotomist, or other certified technician draws it, it might ferment. Fermented blood has more alcohol in it than a properly stored sample. Reviewing reports and records, your attorney can determine whether anything went awry from the moment your blood was taken to the moment it was analyzed. A misstep may be grounds for a dismissal of the evidence.
  • Illegal stops and/or arrests: In a DWI matter, you have rights throughout the process. For instance, you cannot be stopped or arrested without reason. If the officer who pulled you over can't articulate why they did so or why they eventually arrested you, they have violated your Fourth Amendment rights. Additionally, if you didn't give your consent for a blood draw and the officer did not get a warrant to compel you to submit to the test, they have again violated your protection from unreasonable searches and seizures. Depending on the circumstances, such violations can give rise to a valid challenge to the blood test results.

Although the above are a few possible challenges to a blood test, it's important to note that not all DWI cases are the same. What may apply to one may not apply to another. To determine whether your BAC results can be challenged and what defenses may be raised in your case, speak with a defense attorney about your situation.

If you've been accused of drinking and driving in Dallas, contact Hamilton Grant PC at (214) 225-7117 today. Your initial consultation is free.