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DWI Lawyer for Blood Tests in Houston, TX

Learn the Role Blood Tests Play in a DWI Arrest in Texas

It is an all too common scenario that happens every day in Texas. You pulled over for a traffic stop, and the police officer suspected you of driving while intoxicated due to alcohol and/or drugs. You take the roadside sobriety tests. The officer says you failed. But you know you're not drunk or otherwise illegally intoxicated. Regardless, you have been arrested for suspicion of being intoxicated. At the police station, the officer says he wants a blood sample. You say yes, so one is taken, or else, you say no, and he calls for a search warrant, obtains it, and then takes your blood sample anyway. Maybe you were arrested on a "No Refusal" weekend, during which time an officer doesn't need your consent, only a search warrant obtained after swearing to probable cause. Either way, you are forced to provide a blood sample. After you are released from custody, it takes weeks before the blood results are known. When it comes back, the result is a BAC greater than the legal limit of 0.08%. That's not right, and you know it.

Far too often, victims of a falsely inflated blood test think if the tests say so, it must be so. They do not fight the DWI charge or hire an experienced lawyer who knows how to demonstrate that blood testing in their case was inaccurate and unreliable. The people who give up and plead guilty expose themselves to more than just potential fees and jail time. A DWI conviction is often followed by difficulties with such things as job applications, attainment or renewal of professional licenses or security clearance, admissions to college, obtainment of financial aid, and other potential matters, including child custody issues. With the stakes so high, regardless of guilt or not, you must fight a DWI charge. You need to hire an experienced and Board Certified DWI defense lawyer like Doug Murphy.

At Doug Murphy Law Firm, P.C., we understand that people make mistakes. We also know that law enforcement agents make mistakes, especially in the administration and management of blood tests. If you or a loved one has been arrested for DWI, contact Doug Murphy today to discuss the unique circumstances of your case.

What Does Texas Law Say About Blood Tests?

A blood test for DWI purposes is a drawing of your blood by a qualified person, usually at the police station, hospital, or other qualified location, and then the testing of the blood sample through the process of gas chromatography to determine what your BAC level is. Blood tests—when conducted correctly—are generally more accurate than breathalyzers, and thus, many suspected persons—aware of the problems of breath tests—commit to a blood test—unaware that there are just as many problems associated with blood tests, too.

If you are suspected of driving while intoxicated, an officer may request that you take a blood test. The requirements for a blood test in a DWI situation are governed by the Texas Transportation Code §724.012 The Code indicates that "[o]ne of more specimens of a person's breath or blood may be taken if the person is arrested and at the request of a peace officer having reasonable grounds to believe the person" was "intoxicated [while] operating a motor vehicle in a public place."

The Code also indicates when a blood draw is mandatory. An officer is required to take a blood specimen from a suspect when certain conditions apply:

  • There was an accident and someone died or was seriously injured, and the officer reasonably believes one driver was driving while illegally intoxicated.
  • The suspected driver was driving while intoxicated with a child passenger.
  • The suspected driver has been previously convicted of any two previous DWI cases, DWI with child passenger, intoxication assault, or intoxication manslaughter.

The Code does not require a warrant for a blood test in cases where a suspect refuses, but an experienced and qualified DWI attorney Doug Murphy knows how to successfully challenge blood draws that occur under one of these scenarios where blood was taken without a search warrant. In State v. Villareal, 475 S.W.3d 784 (Tex. Crim. App. 2014), however, the Court of Criminal Appeals made it clear that a warrant is required. If a warrant is not properly obtained, the blood specimen can be suppressed as evidence. Thus, if you refuse a blood test, the officer must obtain a warrant.

To obtain a Blood Search Warrant in Texas, the officer must apply for a blood search warrant. A justice of the peace, who acts as a magistrate and who is an attorney licensed by the state of Texas, is authorized to issue a warrant. If the justice of the peace is not an attorney, then he or she may issue a warrant only under certain conditions in accordance with Code of Criminal Procedure, Art. 18.01(i). The same article permits Blood Search Warrant applications via telephone or other reliable electronic means.

What Are Common Problems With the Blood Test Process?

Don't ever assume that because your blood test says one thing, it must be what it is. When it comes to blood tests for DWI purposes, this can be far from the truth. A thorough investigation can lead to startling discoveries or problems with your blood test. Always choose to find an experienced attorney and boardBCertified DWI attorney with a deep understanding of blood testing to represent you on your case. Below are some of the more common problems associated with DWI blood testing:

Collection & Storage of Blood Sample

To be accurate, collecting the blood sample should be timely, and storage of it should maintain its integrity. But this is not always the case. First, the blood alcohol content in a person's system rises over time. If you are taken to the police station, and then certain circumstances prevent immediate blood withdrawal (i.e., waiting for a blood search warrant approval), your alcohol content can very well be higher than what it was at the time you were driving your vehicle. Compounding the time factor is the metabolization factor. We all metabolize alcohol at different rates: a smaller person will process the alcohol at a rate quicker than a larger person. The period of time that expires between consuming alcohol and peak blood alcohol content level varies; you could have been driving before or during the time your BAC spiked. This matters because you may not have been driving while intoxicated at the time of your arrest. Thus, timely collection of a blood sample is crucial to the prosecution's case, and anything else should be exposed and argued.

Second, the drawing of blood is a medical procedure, but many times, the task is completed by someone without an extensive medical background. Minimal understanding of the procedure can and does result in errors that impact the integrity of the sample, which makes it another problem with the collection of blood.

Third, the storage of the blood specimen matters. The blood must be stored properly while it is handled by various people. Improper storage can impact the integrity of the specimen. Delays or improper storage can create conditions that permit fermentation, and fermentation is the process of forming alcohol. If fermentation occurs, the amount of alcohol in the blood specimen will increase, and thus result in a false BAC reading.

Chain of Custody

Blood samples go through multiple hands before they are tested. Each person could—potentially—fail to perform some required aspect of their duty while handling your blood specimen. For example, someone may initially fail to seal the specimen properly, someone may label it inaccurately, or someone may delay transporting the sample from one place to another place. Whatever the failure is, and regardless of whether it's conducted by one or more individuals, one failure means a contaminated sample, and that means the results may be inaccurate.

The Blood Test & its Results

Blood samples are usually tested for blood alcohol content through a machine known in Texas as a gas chromatograph. The results from this process, however, can be more presumptive than definitive. In gas chromatography, the process is very complex, but in very simple terms, it goes something like this:

  1. Blood is transferred into a vial, half-full.
  2. The vial is heated.
  3. Alcohol - a volatile substance - evaporates: in theory, the air filling the other half of the vial contains the proportionate amount of alcohol that can be found in your blood.
  4. A needle is used to take a sample of the air: in theory, the sample in the needle contains the alcohol molecules, which in theory contains the proportionate amount of alcohol found in the blood.
  5. The sample is transferred by transfer gas to a part of the machine known as a "column." Here, a fire flame is used to burn the contents of the sample. The reaction is measured, and the data is processed by a computer software program.
  6. A chromatogram report is produced. However, this report is complicated and often misunderstood; only experienced attorneys can identify and interpret the data. In fact, this is why it is crucial for your defense to have an experienced attorney, because most defense attorneys will accept the results as fact, but an experienced one knows this is far from the truth in many cases and can discern problems through investigation and analysis.

In addition to inherent possible problems with the test itself, the results can be negatively impacted by any delay in the collection of the sample or with a blood sample that has been contaminated either through fermentation or other means. As to the former point, some prosecutors will attempt to correct the time issue via retrograde extrapolation, a process used hours later to determine BAC. An officer requires specific information from you for this process to kind-of work. They will want your weight, time of last drink, and drinking duration. The problem is: they don't ask about other factors that can contribute to your BAC level, such as what you ate, your sex, or your health. Additionally, if fermentation happened, this machine cannot determine or distinguish if the fermentation process caused the BAC result or if it was from any alcohol in the system prior to fermentation.

Do I Need an Experienced Lawyer to Challenge My Blood Test in a DWI Case?

Yes, if you want to avoid a DWI conviction. A lawyer who does not routinely handle and challenge DWI blood tests will not know what to look to beat a blood test.

An experienced DWI lawyer knows the police units and all the tactics each individual unit uses to acquire blood samples. An experienced DWI attorney also knows the prosecution team and the judges. Finally, an experienced DWI lawyer knows the blood testing process, can identify problems, and can interpret the chromatogram report, which is an important accomplishment all on its own. DWI cases involving blood tests can be very complex and technical. Get an attorney, but not just any attorney, a Board Certified DWI and a Board Certified criminal defense attorney. In Texas, you only have two attorneys that fit the bill, and one is right here in Houston: Doug Murphy. The combination of his experience, passion, trial skills, and deep understanding of the entire DWI system is best suited to protect your best interests.

Contact a Resourceful Houston, Texas DWI Lawyer for Blood Tests

At Doug Murphy Law Firm, P.C., we devote our resources and capabilities to defending our clients' rights. We have decades of proven experience and a reputation earned in the courtroom for successful results. Attorney Doug Murphy is a Board Certified criminal defense lawyer and a Board Certified DWI lawyer who not only fights on behalf of his clients but constantly gives back to the legal community to teach other attorneys how to do the same. Contact Doug Murphy online or at 713-229-8333 today to discuss the circumstances of your case.

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