What You Need to Know about Chemical Tests of Blood Alcohol Concentration. Were you asked to submit to a blood or breath test following a Fort Worth DWI arrest?

If a police officer in Fort Worth or the surrounding areas arrests you on suspicion of DWI, the officer will usually ask you to submit to a chemical test of blood alcohol concentration (BAC) by way of a blood or breath test. While either BAC chemical test may be employed, the officer may exercise discretion in terms of which type of DWI test to administer, breath tests are the most common option because the breath testing device is located at the jail.

When the officer elects to administer a blood test, you usually will be transported to a local hospital to have a blood specimen extracted by qualified medical professionals. When the blood test is performed by qualified technicians in compliance with the applicable procedures and protocols, blood tests are the more accurate measure of BAC level.

Can I refuse to consent to chemical testing of my blood or breath if I am arrested for DWI?

While Texas law generally prohibits an officer from forcibly extracting a blood sample if you refuse with certain exceptions indicated below, there are consequences for such a refusal under the Texas “implied consent” law. The implied consent law essentially provides that any driver who applies for a license is deemed to give consent to a BAC chemical test of blood or breath when arrested for DWI. Refusal to comply with the implied consent law can be used against you in court and could result in an administrative suspension of your driver’s license for 180 days. Even if you do not consent to chemical testing of your blood or breath, you may still be prosecuted for DWI.

What if the officer wants to take my blood despite my refusal to give consent?

Even if you refuse to voluntarily provide a blood sample for chemical testing of your BAC level, the officer may seek a warrant to extract blood for such testing. The warrant may be granted by a magistrate if the officer has sufficient evidence to constitute probable cause that you were driving while intoxicated. Because extracting a sample of your blood without your consent constitutes a “search and seizure” under the Fourth Amendment, the officer must comply with the Texas Code of Criminal Procedure in obtaining the warrant based on an affidavit that articulates sufficient evidence to constitute probable cause to believe you were driving while intoxicated.

Will blood test results obtained without my consent or a warrant be thrown out?

While the general rule is that an officer must have a warrant based on probable cause and signed by a magistrate to forcibly extract your blood for a BAC chemical test, Texas law provides a number of exceptions to this general rule when drivers are involved in accidents that result in the following:

  • If you have at least two prior convictions for DWI
  • If you were involved in an accident where someone was seriously injured or died
  • If you have a prior conviction for DWI, and you were transporting a child under 15

Those arrested for DWI who are forced to provide a blood specimen for testing should speak to an experienced Fort Worth DWI Attorney. If you have any questions regarding chemical testing of blood or DWI, we invite you call a Fort Worth DWI lawyer at the Fulgham Law Firm P.C. Call us at 817-886-3078 to discuss the specifics of your case.