A blood test for DWI in Texas is a chemical test used to measure your blood alcohol concentration (BAC). This is a scientific analysis performed to measure the amount of alcohol or other intoxicating substances present in an individual’s bloodstream.
In Texas, law enforcement officers have the authority to request a blood sample from a driver if they have reasonable suspicion that the person is operating a vehicle while impaired. A Texas DWI lawyer can build your defense if you face charges of driving while intoxicated.
When and How a Blood Test is Collected in a DWI Case
In Texas, law enforcement officers have specific procedures and protocols to follow when collecting a blood sample for a DWI blood test. The circumstances surrounding the collection process are crucial, as they can impact the validity and admissibility of the evidence in court.
A Texas criminal defense lawyer can determine if your blood test was done according to the law under Texas Transportation Code Chapter 724, Section 724.012.
When a Blood Test May Be Requested
In Texas, a police officer can request you submit to a blood test when the following occur:
- Reasonable suspicion: If an officer has reasonable suspicion that a driver is impaired by alcohol or drugs, they may request a blood test. This suspicion can arise from various factors, including the driver’s behavior, appearance, performance on field sobriety tests, or the presence of an open container in the vehicle.
- Refusal of breath test: In some cases, if a driver refuses to submit to a breathalyzer test, the officer may seek a warrant to obtain a blood sample instead.
- Serious injury or fatality: If a DWI incident results in serious bodily injury or death, the officer is required by law to obtain a blood sample from the driver, regardless of their consent.
The Blood Sample Collection Process
The process for collecting a blood sample in a potential DWI case includes the following protocol:
- Trained medical personnel: Under Texas Transportation Code Section 724. 019 (a), only trained medical professionals, such as nurses, phlebotomists, or qualified technicians, are authorized to draw blood for a DWI blood test in Texas. Law enforcement officers are not permitted to perform this task.
- Proper procedure: The medical professional must follow strict protocols to ensure the integrity of the sample. This includes using sterile equipment, properly labeling and sealing the sample, and maintaining a secure chain of custody.
- Consent or warrant: In most cases, the officer must obtain the driver’s consent or secure a valid search warrant before compelling the blood draw. However, in certain situations, such as when the driver is unconscious or the case involves a serious injury or fatality, implied consent may be invoked, and a warrant may not be required.
- Timely collection: The blood sample should be collected as soon as possible after the suspected DWI incident to ensure an accurate representation of the driver’s blood alcohol or drug concentration at the time of driving.
Deviations from the proper procedures or violations of the driver’s rights during the blood sample collection process can potentially undermine the admissibility and reliability of the evidence.
Challenging the Results of a DWI Blood Test in Texas
While a DWI blood test is often considered powerful evidence in a driving while intoxicated case, it is not infallible.
There are various legal and scientific strategies that an experienced DWI defense attorney in Dallas may employ to challenge the accuracy and admissibility of the blood test results.
Questioning the Chain of Custody
A critical aspect of maintaining the integrity of a blood sample is the chain of custody, which refers to the documented trail of individuals who handled the sample from collection to testing. If there are any breaks or irregularities in the chain of custody, it may raise doubts about the sample’s integrity and the reliability of the test results.
Analyzing the Collection Procedures
The manner in which the blood sample is collected can significantly impact the test results. A skilled attorney may scrutinize the collection process to identify any potential deviations from established protocols, such as improper handling of the sample, contamination, or errors made by the medical personnel involved.
Challenging the Testing Laboratory’s Procedures
Accredited laboratories must adhere to strict guidelines and quality control measures when analyzing blood samples for DWI cases. An attorney may investigate the laboratory’s procedures, equipment calibration, and personnel qualifications to identify any potential sources of error or inconsistencies that could undermine the test results.
Exploring Alternative Explanations
Certain medical conditions, medications, or physiological factors can sometimes produce elevated or inaccurate BAC readings. An attorney may explore these potential alternative explanations and present expert testimony to challenge the test results’ validity.
Addressing Retrograde Extrapolation
In some cases, the prosecution may attempt to use retrograde extrapolation to estimate the defendant’s BAC at the time of driving based on the blood test results obtained later. However, this process involves complex calculations and assumptions that can be challenged by an experienced attorney.
Evaluating the Officer’s Observations
While a blood test is a scientific measure, it is not the only evidence considered in a DWI case. An attorney may scrutinize the officer’s observations, field sobriety test administration, and other factors to identify potential inconsistencies or weaknesses in the overall case against the defendant.
What Happens if You Refuse a DWI Blood Test in Texas?
Under the state’s implied consent law of Texas Transportation Code 724.011, drivers are deemed to have consented to providing a breath or blood sample when arrested for DWI.
Refusing a blood test can lead to an automatic license suspension, typically for 180 days for a first offense. Additionally, the refusal itself can be presented as evidence of guilt in court and may result in enhanced penalties if convicted of DWI, including longer license suspensions, mandatory ignition interlock device installation, and even potential jail time.
Call Us to Learn More About Blood Tests for DWI in Texas
Facing a DWI case involving a blood test can be a daunting and overwhelming experience. Remember that you have rights and that the evidence against you, including the blood test results, can be challenged by a DWI defense attorney.
At the Law Offices of Randall B. Isenberg, our team understands the nuances of DWI law and the scientific principles behind blood alcohol testing. We have more than 30 years of combined legal experience. Call us today.
