The Chemical Test for DUI
Riverside, San Bernardino, Los Angeles & Orange County
DUI Criminal Lawyer & Attorney

Under the law in the State of California, anyone suspected of, and arrested for, suspicion of driving under the influence is required to submit to a chemical test (breath or blood) to determine the blood alcohol concentration of that person. Generally, the investigating officer, after* placing you under arrest, will ask you whether you would prefer to submit to a breath or blood test.  It is your option, unless, for some reason one of these tests is not available at the station you are being brought to you (either because a nurse is not available to draw blood or a breath testing machine is not present/working at the location).  A refusal to submit to such a test is a separately charged criminal allegation and may carry higher potential jail sentences.  Furthermore, even if you refuse to provide either sample, the arresting police agency can elect to force a blood draw from you to obtain the sample anyway.

*The Preliminary Alchohol Screening Test (“PAS Test”):

Do not confuse the mandatory breath/blood test with the in-field preliminary alcohol screening test that is not required by law.  The preliminary alcohol screening (“PAS”) test is an in-field breath test that an investigating officer may have asked you to submit to.  Furthermore, even though you can refuse, the officer may not have been required to inform you of your right to refuse.  Therefore, you may have submitted to both a PAS test as well as to a chemical test thereafter.  This distinction is important because the PAS test is usually done in close proximity to the time of driving and the prosecution will argue it’s accuracy as to the level of your BAC.  Your skilled DUI defense attorney from WILL & WILL, LLP, however, knows that these tests are sometimes inadmissible at a trial and will utilize their knowledge and experience to keep these results out, or only allow them to be used as another FST.

The Breath Test
If you chose to provide a breath sample, you were asked to blow into the breathalyzer machine two times. The reason for providing two separate breath samples is to test for correctness in the results.  What the tester is looking for are two samples within .02% of each other in order for them to be considered accurate. There are also many factors that can affect the breath sample you provide. For example, if you burped or threw up within 15 minutes prior to blowing into the machine you would have a higher concentration of alcohol in your mouth, commonly referred to as “mouth alcohol” and would therefore give a false higher reading. For this reason, the law (pursuant to Title 17) requires that the investigating officer physically observe you for a full 15 minutes prior to administering a breath test. He/she will be making sure that during that period of time you have any mints,  chew gum, eat, drink, burp, vomit, etc…  This 15 minute time period may include the time during which you performed FST’s, submitted to a PAS, etc…

Attacking the Breath Test
The results obtained from a breath test are generally easier to dispute than those obtained from a blood draw.  The knowledgeable DUI lawyers at WILL & WILL, LLP have many methods they can utilize to attack the validity of a breath sample. 

The following are just two of the requirements that the arresting agencies must live up to in order for the breath test results to be upheld:

The breath machine was properly maintained and calibrated.

Once you decide to submit to a breath test under California’s chemical test requirement, two separate breath samples must be obtained.  Assuming the breathalyzer machine is in working order, there is an acceptable variable of +/- .02% between the two samples provided. If your result is a .08%/.10% that means there’s an allowable error of 20%. That 20% can make a big difference in the outcome of your case. The skilled DUI attorneys at WILL & WILL, LLP know what a great difference this actually is and can utilize such a great discrepancy to argue the ultimate illegitimacy of the results.

The breath sample taken from you was properly obtained.

As previously mentioned, Title 17 of California law requires that the arresting officer observe your physical behavior for a minimum of 15 continuous minutes prior to administering your breath test to prevent improper readings due to “mouth alcohol.”  The testing/investigating officer is making sure that during this period you did not burp, belch, regurgitate, or vomit and did not eat, drink, chew gum, have breath mints, etc...  In addition, assuming you were properly observed for the full 15 minutes, you may have a pre-diagnosed medical condition which makes you an improper candidate for breath testing. Your WILL & WILL, LLP defense lawyer can discuss possible medical defense that you may have.

When you choose to hire the experienced and knowledgeable DUI defense attorneys at WILL & WILL, LLP to represent you in a DUI case where you have provided a breath sample for analysis, our lawyers will review all discovery related to the breath test to ensure that it was obtained properly and that it is accurate.  If there is any basis upon which to attack the validity of the sample provided, we will find it!

The Blood Test
If you elected, on the other hand, to provide a blood sample, the officer will bring you to an area with a licensed nurse who will do the blood draw.  This may occur at the station, or at a local hospital.  While breath test results are available immediately, blood test results are not.  You are usually able to obtain the results of a blood draw 1-2 weeks after the arrest date.  Once you receive the results of your blood test, you should contact your DUI defense attorney at WILL & WILL, LLP immediately.  In the event the results are in question, we have experienced independent criminologists that can re-analyze a split of the blood that was drawn from you after the DUI arrest.