I am Joel Brand, and I defend DUI cases across California. If you took a blood test after a DUI arrest, you probably feel like the number on the lab report is the final word. It is not. California has strict rules for how blood is drawn, stored, and tested. Those rules are called Title 17. When the police or the lab break those rules, the result can be challenged. This post explains what Title 17 requires, how chain of custody works, and how you generally have the right to get your blood sample retested by an independent lab.
What Is Title 17 in a California DUI Case
Title 17 of the California Code of Regulations is the set of rules that controls forensic alcohol and drug testing. It applies to breath tests and blood tests in DUI investigations. The rules cover who can draw blood, how the equipment must be maintained, how samples are labeled, and how they are stored. The purpose of Title 17 is to make sure test results are reliable. If the people handling your blood did not follow these regulations, the test result might not be as solid as the prosecution claims.
Who Is Allowed to Draw Your Blood
Under Title 17, only qualified people are supposed to draw blood for a DUI test. This usually means a trained phlebotomist, a nurse, a doctor, or another medical professional. The person drawing your blood must follow accepted medical practices. If someone without the proper training drew your blood, or if the draw was done in a way that risked contamination, that is a problem. I look at who performed the draw and whether they followed the rules.
How the Blood Must Be Drawn and Handled
The blood draw itself must follow specific procedures. The skin should be cleaned with an antiseptic that does not contain alcohol. The tubes used to collect the blood must contain a preservative and an anticoagulant. The preservative stops fermentation. The anticoagulant stops the blood from clotting. If the wrong amount of preservative is in the tube, or if the tube is not mixed properly, the blood sample can ferment. Fermentation can actually create alcohol in the tube, meaning the test result could be higher than your true blood alcohol level at the time you were driving.
Chain of Custody in a DUI Blood Test
Chain of custody is the documented trail of everyone who handled your blood sample from the moment it was drawn to the moment it was tested. This includes the phlebotomist, the officer who transported it, the lab technician who analyzed it, and anyone else who touched it. Every transfer must be recorded. If there is a gap in the chain of custody, we do not know what happened to the sample during that time. A broken chain of custody means the sample could have been tampered with, mislabeled, or stored improperly. This can undermine the reliability of the result.
Storage and Preservation of Your Blood Sample
Title 17 has rules for how blood samples must be stored. They need to be refrigerated to prevent degradation and fermentation. If a sample sits in a hot police car or an unrefrigerated room for a long time, the test result could be compromised. I always ask for the storage logs. I want to see when the blood was drawn, when it was logged into evidence, and when it was placed in a refrigerator. If the timeline shows the sample was not stored correctly, that is a defense I can raise.
Your Right to an Independent Retest
In California, you generally have the right to a portion of your blood sample so it can be retested by an independent laboratory of your choosing. This is one of the most important rights you have after a blood test DUI. An independent lab can check the blood alcohol concentration themselves. If the independent result is different from the crime lab result, or if the independent lab finds problems with the sample, that information can be used to challenge the case against you. If you want a retest, it needs to be done quickly before the sample degrades or is destroyed.
How a Retest Can Help Your Case
A retest can help in several ways. Sometimes the independent result comes back lower than the crime lab result. This can cast doubt on the accuracy of the prosecution's evidence. Sometimes the independent lab finds that the preservative was insufficient or that the sample was contaminated. In some cases, the crime lab has already consumed the entire sample. If the state destroyed the sample before you had a chance to retest it, that can be a due process issue. To understand how this fits into a broader strategy, you can read about the top DUI defenses and the broader California DUI defenses guide.
What Happens If the Sample Is Unavailable
Sometimes I request a retest and we learn the sample is gone. The lab may have used it all, or it may have been destroyed according to routine policy. When the government destroys evidence that you had a right to test, it can weaken their case. Courts recognize that defendants have a right to examine the evidence against them. If that evidence is gone through no fault of your own, a judge might limit the prosecution's ability to use the original test result, or in some situations the result could be excluded entirely. Every case is different and outcomes depend on the specific facts.
Common Title 17 Violations I Look For
When I review a blood test case, I look for several common issues. Did the person who drew the blood use an alcohol swab? Were the tubes expired? Was the blood mixed properly after the draw? Was the sample refrigerated promptly? Is the chain of custody complete and unbroken? Did the crime lab follow its own protocols? Any of these issues can be a starting point for a defense. You can also review the California DUI FAQ for more general information.
Blood Tests Versus Breath Tests
Breath tests and blood tests have different strengths and weaknesses. Breath test machines can have calibration issues. Blood tests are generally considered more accurate, but they are still subject to human error. The advantage of a blood test for you is that a blood sample can be retested. A breath sample is usually gone after you blow into the machine. This means a blood test gives us an opportunity to verify the result independently. If you are facing a license suspension, you should also understand how a DUI affects your license and how the DMV hearing works.
The Timeline for Requesting a Retest
Time is critical. Blood samples do not last forever. Even when refrigerated, they can degrade over time. The sooner you contact a lawyer, the sooner a retest can be requested. If you wait too long, the sample may have degraded to the point where a retest is meaningless. In some situations, the lab may destroy the sample after a certain period. Acting quickly protects your right to a retest and gives us the best chance of getting a reliable independent result. For a sense of what to do right away, see the first 10 days after a DUI.
How Title 17 Issues Affect the Court Case
Title 17 violations do not automatically mean a case gets dismissed. However, they give me leverage. If I can show the blood sample was not handled properly, I can file a motion to suppress the evidence. I can also use the violations during cross examination of the lab analyst. The goal is to create reasonable doubt about the accuracy of the test result. Prosecutors sometimes offer better resolutions when they know their evidence is weak. To see how this plays out, read about how DUI cases get dismissed or reduced and the DUI court process step by step.
Why You Should Not Assume the Blood Test Is Perfect
Many people assume that because a blood test is scientific, it must be accurate. Science is only as good as the people doing the work. Phlebotomists make mistakes. Officers make mistakes. Lab technicians make mistakes. I have seen cases where the blood draw was done improperly, where the chain of custody had gaps, and where the storage was questionable. You should never assume the test result is untouchable. Let me look at the details. To understand the potential penalties you are facing, review the California DUI penalties guide and first offense DUI penalties.
What I Do When I Review a Blood Test Case
When I take a blood test case, I start by getting all the records. I get the police report, the lab report, the phlebotomy report, and the chain of custody documents. I request the storage logs. I look for any deviation from Title 17. If there are problems, I request a retest at an independent lab. I review the independent results and compare them to the crime lab results. Then I build a defense strategy based on what I find. Every case is fact specific, and I cannot guarantee a particular outcome, but I can promise I will examine every detail.
If you have been arrested for a DUI in California and you took a blood test, I can help. I offer a free written case analysis on this page. Call me at (888) 271-6644. I answer my own phone, 24/7. You can also read more from the DUI blog.