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Warrant Requirement for Blood Alcohol Tests


In typical DWI cases, the police will require a warrant to legally draw a blood sample from you if you are stopped or arrested for a DWI. Like a breathalyzer or breath test, a blood test is used for measuring a person’s blood alcohol content (BAC) after being arrested for DWI. During a blood test, a qualified medical professional will obtain blood from the arm and place it in a vial that will be sent to a laboratory for evaluation.

When Can The Police Take My Blood Without a Warrant?

Compared to breath tests, blood tests usually provide more accurate test results when determining a person’s BAC. Because of this, the police will typically try to obtain a blood sample from a suspected DWI offender since the blood test’s accuracy will serve as better evidence for their DWI case against the offender. Under the law, the police can forcibly draw blood without your consent or a warrant under the following circumstances:

  • If you were driving a car that was involved in a crash and the police officer has probable cause to believe that the crash occurred because you were driving while intoxicated
  • If the police officer has probable cause to believe that a person was killed or may be killed in the crash
  • If another party involved in the crash, other than you, has sustained bodily injuries or has been sent to the hospital to receive medical attention
  • If you had a minor passenger under 15 years old when you were stopped for a suspected DWI
  • If you have been previously convicted of an intoxication assault, intoxication manslaughter, felony DWI, or DWI with a minor in the car
  • If the police have obtained credible information that you have been placed under community supervision

Under these circumstances, the police also have the right to choose which kind of specimen, whether breath, saliva, or blood, must be taken from the suspected DWI offender. But outside the scenarios above, the police are not legally allowed to perform a blood test.

It is also crucial to note that if the police served you a warrant before being forced to undergo a blood test, they must have followed the proper procedures for the court to admit into evidence the blood test result. So, while the police can force you to undergo a blood test without your consent through a valid warrant, if they fail to observe specific procedures, your blood test result may not be admissible in court.

Seek Legal Guidance From a Seasoned DWI Attorney in TX

If you were arrested for DWI and forced to undergo a blood test and you’re unsure whether the test was legal, contact Hoelscher Gebbia Cepeda PLLC right away. Our experienced TX DWI attorney will thoroughly all the evidence against you, including the blood test result, and review how it was collected, handled, and tested to determine how we can challenge it. Arrange your appointment with our DWI attorney in TX by calling 210-222-9132 or contacting us online.