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Blood Test Defense

Many states have outlawed routine blood draws after a misdemeanor DUI or DWI arrest. In Texas, however, local law enforcement agencies have started forced blood draws after a suspect refuses to submit to chemical testing.

Called ”no refusal” weekends, these events are highly publicized in order to deter people from drinking and driving. In some cases, the person is strapped down and restrained by force while the blood is drawn with a needle.

Blood Test in Plano DWI

For attorneys, these type of cases presents a multitude of constitutional challenges that can be brought through motions to suppress the blood evidence and test results.

If you were subjected to blood draw after a DWI arrest by an officer with the Collin County Sheriff’s Office, or a police officer with the police department in McKinney, Frisco, Wylie, Allen or Plano, then contact an attorney with Law Offices of Richard C. McConathy.

Overview of Fighting DWI Blood Test Results

Constitutionality of Forced Blood Tests in Texas

The court of criminal appeals in Texas has explained that “the Supreme Court's holding in McNeely makes clear that drawing the blood of an individual suspected of DWI falls under the category of cases holding that ‘a warrantless search of a person is reasonable only if it falls within a recognized exception’ to the warrant requirement.” Villarreal, 2014 WL 6734178, at *20 (quoting McNeely, 133 S.Ct. at 1558) (emphasis added).

The court of criminal appeals emphasized that the McNeely Court “explained that such an intrusion implicates an individual's ‘most personal and deep-rooted expectations of privacy.’ ” Villarreal, 2014 WL 6734178, at *20 (quoting McNeely, 133 S.Ct. at 1558).

According to the Texas court of criminal appeals, “[t]hese principles from McNeely —the recognition of the substantial privacy interests at stake and the applicability of the traditional Fourth Amendment framework that requires either a warrant or an applicable exception—apply with equal force to this case.” Flores v. State, No. 04-13-00754-CR, 2014 WL 7183481, at *2 (Tex. App. Dec. 17, 2014); Villarreal at *20.

Thus, the court of criminal appeals “reject[ed] the State's assertion that a warrantless, nonconsensual blood draw conducted pursuant to those provisions [of the Transportation Code] can fall under one of the established exceptions to the warrant requirement.” Id. The court of criminal appeals further “reject[ed] the State's suggestion that such a search may be upheld under a general Fourth Amendment balancing test.” Id.

The Texas courts of appeals have found that a blood draw in a routine DWI case was not valid under the:

  1. consent exception to warrant requirement;
  2. automobile exception;
  3. special needs exception; and
  4. search incident to arrest exception.

Additionally, a blood draw is not valid as a general Fourth Amendment balancing test. Id.

Challenging Results of a Consensual Blood Test

Many people ask, “I took a blood test for a DWI. Can I beat the case? What happens next?” Call our office for a free consultation so that we can answer your questions.

The issue in a DWI blood test case is whether the Assistant District Attorney with the Collins County District Attorney’s Office can get the breath test results into evidence at trial. In these cases, the defense will fight to have the results suppressed or excluded. If the results are admitted at trial, the defense will show problems with the results and its accuracy.

Challenges can be brought to the collection, storage, and testing of the blood sample with a machine known as a Gas Chromatograph.

Finding A Collin County Attorney to Fight DWI Blood Tests

At Law Offices of Richard C. McConathy, we will seek the best possible defense if prosecutors have the results of a blood test, including challenging the constitutionality of the test, bringing forth scientific evidence showing reasonable doubt about the results or more. Call an experienced criminal and DWI defense attorney at Law Offices of Richard C. McConathy to discuss your case and your best defense.


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DWI Blood Test Case + Prescription Meds
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DWI Breath Test Refusal
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5700 Granite Pkwy #200
Plano, TX 75024

405 SH 121 Bypass #A250
Lewisville, TX 75067

Principal location
15110 Dallas Pkwy #400
Dallas, TX 75248


Office: (972) 805-8855

Fax: (972) 239-0398