DWI Blood Tests

Houston DWI Blood Test Lawyer

Texas is similar to other states in enacting criminal laws designed to deal with people who operate motor
vehicles while they are intoxicated
. Although prosecutors can prove a person was driving while
intoxicated using testimony of the arresting officer’s observations of the motorist, evidence of
the person’s blood alcohol concentration (BAC) makes it easier for a prosecutor to
prove beyond a reasonable doubt that the person was legally intoxicated.

If a motorist refuses to submit to a DWI blood test, the police can take a blood sample by force under the following circumstances:

  • The motorist was involved in an accident in which another person suffered serious physical injuries, died or might die from the injuries sustained in the accident.
  • There was a passenger under 15 years of age in the DWI suspect’s vehicle.
  • The suspected DWI motorist has previously been convicted of intoxication manslaughter or intoxication assault.
  • The motorist has two or more prior DWI convictions.

Blood Tests for DWI in Texas

According to the Penal Code, a BAC of 0.08 percent is the legal limit for intoxication in Texas. The usual procedure is for the arresting officer to ask the motorist to submit to chemical blood testing through a breath test or by giving a blood or urine sample.

Defending Against Blood Tests for DWI

  • The blood sample not drawn by a doctor, qualified technician, chemist, registered nurse or licensed vocational nurse
  • The blood sample was not drawn in a sanitary location
  • Negligence in the taking or handling of the blood sample
  • Improper storage of the blood sample
  • Failure of the police to maintain a proper chain of custody in handling the blood sample
  • Lack of probable cause by the arresting officer to stop the motorist
  • A warrantless blood test was administered without at least one of the statutory exceptions

The Penalties for Refusing a DWI Blood Test

Motorists in Texas are deemed to have consented to have their blood or breath tested when asked by a police officer. This implied consent rule of the Transportation Code imposes a mandatory license suspension upon any motorist who refuses to submit to testing. The suspension is 180 days for a first refusal and two years for a person with two or more refusals.


If you have been arrested and charged with a DWI, the law office of Rand Mintzer, Attorney at Law can assist you.

Protecting your rights, developing an aggressive defense strategy and challenging DWI blood test results should start as soon after your arrest as possible, so schedule a free consultation with Rand Mintzer today at 713-862-8880.

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