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DWI Blood Test

Police officers use chemical tests to determine a person’s impairment level. However, when controlled substances are involved it can be a little more difficult. Law enforcement may ask you to submit to a blood draw to determine if any narcotics are in your system while driving.

Blood tests for DWI can be tricky. This is because blood analysis is the most accurate out of the three chemical tests. It also requires a scientific background to read the results in comparison to breath analysis. All of this information doesn’t mean blood tests are without fault. There are many external and environmental factors which could skew your results.

If you or someone you know has been charged with DWI because of a blood draw, it’s imperative you seek legal counsel.

DWI Attorney for Blood Tests in Harris County, Texas

Chemical testing is a tool utilized by law enforcement to determine your impairment level. Unfortunately, not all chemical test readings should be trusted. If you or someone you know has been charged with DWI, it’s imperative you seek legal representation.

Call the attorneys at Flood Lewis & Associates, Inc. for a quality defense. We have represented residents in the Harris County area for years. Contact us at (713) 224-5529 to set up a free consultation today. Flood Lewis & Associates, Inc. defends people accused of DWI throughout the greater Harris County area including Houston, Tomball, Bellaire and West University Place.

Overview of DWI Blood Testing in Texas


Why Do Police Officers Use Blood Analysis for DWI?

Law enforcement uses chemical testing to determine a person’s blood-alcohol concentration (BAC). If their BAC is at .08 or higher, then the officer is legally required to arrest them of DWI. When it comes to controlled substances, however, it’s much more difficult to determine BAC.

This is why officers will sometimes defer to blood analysis if they can’t get a BAC reading of .08 or higher. Blood analysis is considered the most accurate out of the three tests, breath, urine and blood. It can give a much more reliable reading than breath or urine analysis if narcotics are involved. Police officers might also have an unconscious person undergo a blood test if they were involved in deadly accident.


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Problems with Blood Testing for DWI

All chemical tests are susceptible to human error, even blood analysis. Certain external and environmental factors could skew your results and jeopardize your freedom. Factors such as outdated equipment or contaminated samples could lead to false results.

Listed below are some issues associated with DWI blood testing.

  • Contaminated samples;
  • Unsanitary testing conditions;
  • Outdated testing kit;
  • Failure to sterilize medical equipment;
  • Sample decomposition;
  • Mislabeled sample;
  • Poorly stored sample;
  • Alcohol contamination of the sample during sterilization;
  • The sample was taken by an unauthorized person;
  • Inadequate training;
  • Break in chain of custody creating confusion;
  • Inability to convert serum or plasma blood;
  • Second blood test gives vastly different results; and
  • Failing to take two samples

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Should I Refuse Blood Testing for DWI in Texas?

A question many criminal defense lawyers are asked is: “should I submit to blood analysis for DWI?” The answer should be no. Many factors could influence your test and lead to a misleading BAC and a DWI.

It’s important you understand refusing chemical testing may come with some consequences. Your license will be automatically suspended for up to 180 days for refusing a chemical test. Repeat refusals will enhance the suspension term for up to two years.

While it’s a hassle to deal with a suspended license, it’s much easier than a DWI conviction. You can contest your license suspension with an administrative license revocation hearing. The hearing will be a chance for you to hire legal representation and fight your license suspension.

You must know that you could be arrested for refusing chemical testing. Officers reserve the right to arrest you if they have probable cause you were DWI. The police officer could take your refusal as a sign you are intoxicated. You might be booked for a short period of time, but the prosecution may not have concrete evidence against you.


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Additional Resources

Administrative License Revocation Program – Visit the official website of the Texas Department of Public Safety (DPS) to learn more about their ALR program. Access the site to read about their suspension terms, ALR hearing and how to get an occupational license.

Texas DWI Laws – Visit the official website of the Texas Penal Code to learn more about their DWI laws. Access the site to read their penalties, possible defenses and other alcohol-related offenses in Texas.


DWI Attorney for Blood Testing in Houston, Texas

If you or someone you know has been charged with DWI, it’s crucial you seek a skilled criminal defense attorney. You will need strong representation so you can avoid expensive fines and even possible jail time. Call Flood Lewis & Associates, Inc. to speak to an experienced lawyer today.

Our attorneys at Flood Lewis & Associates, Inc. have years of experience with DWI. We can create a sturdy defense plan to protect your freedom. Call (713) 224-5529 to set up a consultation today. Flood Lewis & Associates, Inc. accepts clients throughout the greater Houston metroplex area including Uptown, River Oaks, and Midtown.



This article was last updated on March 13th, 2019.

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