You're headed home from a nice dinner with friends. You had a few drinks but feel perfectly confident to drive. Suddenly, you notice blue lights behind you, and the next thing you know, you're pulled over, asked to step out of your vehicle, and asked whether you prefer taking a DUI breath or blood test.

Unfortunately, this situation is all too common today. Officers pull over California drivers routinely if they suspect they are driving under the influence of alcohol or drugs. To be fair, an officer must judge whether a driver is under the influence. Still, that suspicion can be almost anything, including catching a whiff of beer on their breath from the two drinks they consumed with dinner.

I want to prepare you for this situation by explaining the testing process for blood alcohol concentration (BAC). What are your rights? What are your responsibilities? Let's start with the law of implied consent.

Am I Required to Have a DUI Blood Test?

If you're a California driver with a valid driver's license, the state considers you to have consented to take either a DUI blood test or a DUI breath test when arrested for suspicion of DUI. In other words, you must comply with the law of implied consent . All drivers in the state must submit to testing or face further administrative consequences and possibly increased criminal penalties. The officer is usually required to give you a choice between DUI blood testing and DUI breath testing. Still, a couple of exceptions exist:

  1. If the officer suspects you are driving on drugs, they can require a blood test because breath testing does not accurately detect the presence of drugs in your system. Nonetheless, the law requires officers to offer a breath test. Even if you choose the breath test, they can request a blood test if they suspect the presence of drugs in your system.
  2. If you are unconscious, the officer should request a warrant for a DUI blood test. The same rule applies in the case of a deceased individual. Sometimes officers will try to collect a blood test without a warrant, which may be a Fourth Amendment violation.

Should You Take a DUI Breath Test or a DUI Blood Test?

For most people, breath testing is the preferred option. It's faster, can be conducted on-site, and is not invasive. However, a breath test might be impossible if you have asthma, emphysema, COPD, or other lung or breathing-related conditions. Any condition that prevents you from blowing hard enough into the breathalyzer means blood testing is the better option. There are different defenses in DUI Breath cases vs. DUI Blood cases, and there is no right or wrong option when selecting a test.

One should never refuse a post-arrest chemical test in a DUI case, as DMV will suspend your license for one to three years with no opportunity for a restricted option.

Why Some Drivers Prefer DUI Blood Testing

While many drivers prefer to take a breath test so they can get it out of the way, others prefer DUI blood testing for several reasons, including:

  • Many people consider DUI blood testing a more accurate measure of blood alcohol concentration than breath or, in rare cases, urine testing.
  • Check whether your
  • blood sample was retained for possible follow-up testing. An independent laboratory may reveal substantial evidence if the blood sample is available. Re-testing is expensive, so if there are issues with the state's evidence, they must prove that none of those issues affected your blood alcohol concentration.

Can You Refuse to Take a DUI Blood Test?

While California's implied consent law means that you have impliedly consented to take either a breath or a blood test, you can still refuse to test entirely. Although one has a constitutional right to refuse a blood test, you do not have the right to refuse a breath test if lawfully arrested. However, the same constitutional protections concerning a blood test do not apply at a DMV Administrative Hearing. They can suspend your license for one to three years if you refuse a chemical test.

Are DUI Blood Test Results Always Accurate?

No chemical testing is accurate 100% of the time, including DUI testing. In most cases, I can have my client's charges reduced or dismissed by challenging the test results. Your DUI case may hinge on whether the arresting officer correctly followed California's Title 17 procedures, compromising the blood test results. Sometimes the Crime Lab fails to follow its official procedures or the manufacturer's guidelines. Other times, the scientific community objects to the Crime Lab blood testing procedure.

In addition to the potential for the testing facility to fail in following Title 17 procedures, there's also the fact that BAC can vary greatly. For example, your blood alcohol test results can fluctuate between the arrest and the blood draw.

Understanding California's Title 17 Requirements for a Blood Test

California's Title 17 sets out the requirements for testing a driver's blood. They include the following:

  • Before drawing blood, the technician/medical professional must sterilize the draw site with a non-alcohol-based product since the presence of alcohol could alter the test results.
  • The vial used to collect the blood sample must also contain an anticoagulant and a preservative to help ensure the sample is viable for testing.
  • Reusable equipment used in the process cannot be cleaned with or stored with volatile organic solvents, including alcohol.
  • The chain of custody must remain unbroken and be recorded accurately at every step, from blood draw to testing and afterward.

While the officer must follow Title 17 steps correctly, the court may admit the blood test evidence and allow it to be used against the accused even with clear violations. The jury must weigh the evidence and determine its relevance.

What If My Blood Test Results Are Incorrect?

If your blood test comes back positive, but you were not driving under the influence, your attorney can challenge the validity of the results in several ways. Your DUI Attorney must collect all of the underlying data in a DUI Blood result case to see if there were any errors during the testing process. Sometimes the machine will stop during the run of your sample and will be left on the device overnight and tested the next day which can present problems. Other times, Quality Control may be out of range, compromising your test result. Only a skilled DUI attorney knows what to ask for in discovery and what to look for to ensure you are getting an excellent DUI defense and looking at all relevant information.

Are DUI Blood Tests Reliable?

Most blood test results are assumed to be accurate. However, that does not mean they are. It is up to your DUI defense attorney to question whether Title 17 procedures were followed or if other factors might call the results into question.

Can the Police Require Me to Take a DUI Blood Test?

In short, no, police cannot force you to take a blood test if they suspect you of driving under the influence unless they have a warrant. Even with reasonable suspicion, police officers cannot force citizens to take a blood test. That said, they can force you to take a breath test without a warrant. That precedent was established in Birchfield v. North Dakota when the case when to the US Supreme Court.

So, what does happen if you refuse a blood test? While you cannot be charged with an additional crime, the refusal does carry consequences. First, if you refuse to take a blood test and are then convicted of a separate crime of driving under the influence, you can face an enhanced penalty. As mentioned, you'll also have your driver's license suspended for a year.

Another consideration is that those "enhanced" penalties can have dramatic repercussions after your case. For example, if this is your first DUI and you're over 21, refusal means you cannot obtain a restricted license to go from home to work and back during your suspension period. That makes it very difficult to earn a living.

Things become even more complicated if this is your second, third, or fourth offense. For instance, you'll earn a mandatory two-year license suspension on a second offense. If this is your third offense, you'll face a three to ten-year license suspension.

You may also see other ramifications, including:

  • Additional jail time
  • Increased fines or fees
  • Restrictions on your license or vehicle

If the officer can secure a warrant, they can force you to submit a blood test. If the officer believes you are driving under the influence (whether of drugs or alcohol), they will seek a warrant. In this instance, officers can physically restrain you while your blood is forcibly taken. You will be taken to a laboratory and restrained if necessary while the sample is drawn.

A warrant will also be sought if a driver is found unconscious. A warrant is also necessary if a driver is found dead to determine the cause of death or factors contributing to the cause of death.

Remember that even with a warrant, your blood must be drawn according to Accepted Medical Practices to comport with Fourth Amendment requirements. Suppose your blood was not drawn according to Accepted Medical Practices (i.e., dirty environment, contaminants around, unusual pain, you suffered an injury like a hematoma, etc.). In that case, you may have a Fourth Amendment challenge to try to get the blood evidence suppressed.

Blood Evidence and the 3-Hour Rule

In the world of DUI prosecution, there’s something called the Three-Hour presumption. This is called a permissive inference that a prosecutor can use to argue to a jury that if your blood or breath was taken within 3 hours of the time of driving, then a Judge or Jury can infer that if your blood alcohol concentration was .08% or higher at the time of the test, then they can assume that it was also .08% or more at the time of driving. There is no scientific basis for this, and even the State Expert will agree that this inference is not based on science because your blood alcohol level will not stay the same for that period. It is either going up (rising BAC), you may stay the same for a while (plateau BAC), or you may be eliminating alcohol (decreasing BAC).

Now on the DMV Administrative Per Se (APS) side, if the state does not draw your blood or take your breath within 3 hours of the time of driving, that can be a basis to win your DMV hearing.

How Do DUI Blood Tests Work?

DUI blood tests are typically administered in dirty, unsanitary environments such as the jail. The blood then needs to be immediately refrigerated. The blood is tested in most jurisdictions using headspace gas chromatography to identify alcohol within blood samples. In most cases, blood test results are not immediate and may take up to six weeks to return from the testing lab.

Gas chromatography uses a four-step process: sample collection, sample injection, sample separation, and sample detection. The goal of the process is simple, though. Gas chromatography allows components within a mixture (like blood) to be separated and measured. It can also do this with tiny samples, meaning that only a small part of the blood drawn for testing will be required.

There are many steps, including chain of custody with your blood sample, that needs to be explored by your DUI Attorney and reviewed with you to ensure that the lab followed the correct procedure.

Other Things to Know about DUI Blood Testing in California

Being pulled over and undergoing sobriety testing can be embarrassing, frustrating, and demeaning. It's natural to make mistakes here. Unfortunately, some mistakes cannot be corrected. For instance, you have only one chance to decide whether to submit to a chemical test, and you cannot change your mind afterward. Once you agree, you've agreed and that's that. You also have no right to consult with an attorney before you decide whether to take a blood test (or any form of DUI chemical test, for that matter).

Challenging DUI Blood Tests: Why It Matters

You may have wondered if you have any chance of having DUI charges reduced. There is always hope. Depending on the situation, a skilled DUI attorney can have your case dismissed entirely. It all hinges on your strategy for challenging the charge, and DUI blood testing can provide the means to do just that.

How to Challenge DUI Blood Test Results in Court

In most cases, an experienced DUI attorney will choose one of four strategies to challenge your blood test results. The first is to file a motion to exclude the test results from evidence based on the lack of a warrant and informed consent. Secondly, file a motion to exclude the blood sample on it not being drawn according to accepted medical practices. The third is to attack the officer’s conclusions about your impairment, which could result in a plea bargain or a not-guilty verdict. Fourth, your attorney may challenge the legitimacy of the traffic stop.

Factors That Can Affect Blood BAC Testing

While today’s DUI blood testing technology is much more advanced than anything that came before, it is not 100% accurate. Some surprising factors can affect your readings, including the following:

  • Your age, weight, and gender
  • Radiofrequency interference in the testing process (for breath testing)
  • Mechanical defects/errors
  • Eating before you take the test
  • Operator error
  • The type of alcohol you consume
  • Storage/holding facility errors
  • Technician errors

Let's look at a quick example of how a simple human error can lead to a dismissal.

When Carla was pulled over for not stopping at a stop sign, the officer smelled alcohol on her breath. She'd had a couple of glasses of wine with friends but felt fine and decided to drive home. She agreed when requested to take sobriety tests, assuming her BAC would be very low. However, when her results returned several weeks later, they showed her at .15%, almost double the legal limit.

Worried about facing DUI charges and what a conviction might do to her life, Carla hired an experienced DUI attorney. The attorney, realizing that mistakes happen even in today’s technologically advanced world, began investigating the case.

The video in the case revealed someone who was not displaying any signs and symptoms of DUI intoxication you would expect to see on a .15% blood alcohol level. It turns out the lab didn't follow Title 17 procedure. Further, they had destroyed her blood sample despite a request to preserve it.

Fortunately, a Jury acquitted her of all charges after a week-long Jury Trial based on a Disconnect defense.

DUI Lawyers: Choosing an Attorney with Experience and Expertise

Being convicted of DUI can profoundly affect your life and ability to earn a living. It can be very costly – financially, personally, and professionally. A DUI conviction may affect your ability to get an education, enter a rewarding career, or even enjoy basic privileges like driving a car. It raises your insurance costs – sometimes exorbitantly – and may require completing substance abuse classes or installing an interlock device on your vehicle.

However, a DUI arrest does not have to mean a conviction. Even if you consented to a DUI blood test, working with an experienced DUI lawyer ensures that all your options are explored, and you can mount the best defense possible. An experienced attorney will review the circumstances of your arrest and review your strategy with you. In some cases, a lawyer may have the charges dismissed, particularly if Title 17 steps were not followed or if there were any irregularities in the arrest or testing process.

Joshua J. Price is a 5-star San Diego DUI attorney with over 14 years of experience representing clients accused of driving under the influence. He has successfully saved hundreds of driver's licenses and defended over 2,000 clients during his career. Contact us today to schedule a free consultation .