Blood Test Procedures in California

January 5, 2021

How To Challenge a DUI Blood Test

Blood Test Procedures in California

If you were pulled over on suspicion of DUI in California, law enforcement might draw a DUI blood test to prove you had an illegal Blood Alcohol Concentration (BAC). After an arrest for an alleged DUI, you will likely be offered either a blood or breath test at the police station.

The results of these tests can be used as evidence against you in a subsequent trial for DUI. You cannot refuse to take the tests because you have given your implied consent by driving on California roads. However, you generally can choose either the blood or the breath test.

Why Take a DUI Blood Test Instead of a Breath Test?

To prove that you were driving with an illegal BAC, law enforcement must use a post-arrest blood or breath test to calculate your level of intoxication. The results from a side of the road Preliminary Alcohol Screening (PAS) breathalyzer test are generally not allowed to be introduced as evidence at your trial. The PAS test is only used to determine whether the police have probable cause to arrest you on suspicion of DUI.

Once at the police station, typically, you will be offered the choice of a blood or breath test to determine your BAC. While many people prefer a breath test because it is easier, a blood test can offer more options for your defense.

When you provide a breath sample, there is no residual evidence to be examined by your lawyers. The test only captures your breath at that moment in time and does not store any for future testing.

On the other hand, if you take a blood test, it records the actual amount of alcohol in your bloodstream. This may be a more accurate measure of your BAC than a breath test. Further, a blood test requires a sample to be stored appropriately for future examination.

Proper Procedures for Collecting a Blood Test

Any blood test introduced as evidence against you at a trial can be challenged if law enforcement failed to follow proper collection protocols.

California laws requires all blood tests be collected:

  • As soon as possible after arrest
  • By a trained technician or professional
  • Without using alcohol to sterilize the skin
  • With a proper preservative and other measures to prevent contamination
  • In accordance with evidentiary chain-of-custody practices

A skilled criminal defense attorney can investigate the procedures used to obtain your blood sample for any possible problems.

Validity of Improperly-Collected DUI Blood Test

One thing that experienced defense lawyers will do is have your leftover blood sample retested to assure the original results were correct. If there is a discrepancy in your BAC between the first test and re-examination, your lawyer can call into question the entire testing process.

Even if the results of a second opinion are consistent with your original BAC, your attorney can argue that law enforcement’s testing method violated your constitutional rights. For example, if your blood is drawn by an officer or some other improperly trained employee, the police may have violated your constitutional rights regarding searches and seizures. If you win this type of argument, the blood test cannot be introduced as evidence of your BAC, and the court will likely toss out your case.

If you’ve been arrested on DUI charges in Huntington Beach, California, The Chambers Law Firm can ensure your rights were not violated. Contact us at 855-397-0210 or to request a free consultation with member of our talented legal team.

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