Blood Split Motions in California DUI Cases


California law lets drivers who take a DUI blood test get part of the blood sample for independent testing. To do this, the defense files what is known as a "blood split" motion.

So-called “blood splits” are authorized under Title 17 of the California Code of Regulations (“CCR”).1 (Title 17 also authorizes a "urine split" for in the rare case in which a driver took a DUI urine test.)2

This is the major advantage a DUI blood test has over a DUI breath test. Breath samples cannot be saved for independent retesting later.

To help you better understand “blood split” motions, our California DUI defense lawyers discuss, below:

1. What is a “blood split”?

“Blood split” refers to California's practice of splitting DUI blood samples into two containers. One is used for law enforcement testing of a driver's blood alcohol concentration (“BAC”). The other is saved in case the driver wants to have his or her blood independently retested.3

This only applies if a driver has elected to (or been required to) take a blood test. In cases of suspected DUI of alcohol, most drivers are offered their choice of a blood or breath test.4

Unlike blood samples, breath samples cannot be saved. This is the major advantage to choosing a blood test over a breath test after a drunk driving arrest.

Cases in which a blood test can be required after a DUI arrest

A driver is required to take a blood test when:

  • The officer has a reasonable suspicion that the driver is driving under the influence of drugs (“DUID”)5;
  • A breath testing machine is not available;6 or
  • The driver is unable to complete a breath test (e.g., due to a medical condition or because the driver is unconscious or deceased).7

Drivers who are medically unable to take a blood test are exempted from this requirement.8 And no one can be forced to take a blood test against his or her will, unless the police get a warrant. 9

But there are penalties for a chemical test refusal in California. These include a mandatory one-year driver's license suspension for a California DUI.

2. How a “blood split” motion can help defend against a DUI

Blood split motions can help fight DUI charges by casting doubt on the accuracy of chemical test results. Chemical test results obtained by law enforcement are presumed to be accurate. So the burden is on the defense to show that they are not.10

The easiest way to do this is often with independent test results that show that the defendant had less alcohol and/or drugs in his/her system. This is especially true when the defendant's BAC is higher than the applicable hard “legal limit” for alcohol. But it is useful in any DUI case.

2.1. Use in California “per se” drunk driving cases

California's “per se” DUI laws punish people who drive with a BAC above the legal limit. Thus a blood split test that shows a BAC below that limit can serve to create “reasonable doubt.”

The most common “per se” drunk driving charge is California Vehicle Code 23152(b), driving with a BAC of 0.08% or higher.

Other California “DUI per se” laws that work similarly to Vehicle Code 23152(b) include:

Charges of driving under the influence of alcohol or drugs

Blood tests also figure prominently when DUI charges are not based on a “legal limit” for alcohol or drugs. Charges of this type include:

With these charges, the prosecutor must prove that the defendant's driving was actually impaired by alcohol and/or drugs. 11

In the case of drugs, there is no consensus as to what amount of drug use results in impaired driving.12

And the “legal limit” for alcohol is a useful fiction, rather than a level at which every single person will be too drunk to drive. It is merely the level at which the prosecutor no longer has to prove impairment.

This means that chemical tests will never be conclusive when someone's BAC does not exceed the applicable legal limit.

But when a prosecutor shows a borderline test result along with other evidence (such as bad driving or poor performance on field sobriety tests) it can be enough to convince a jury there is no reasonable doubt. So it is still useful to discredit the original BAC results.

hand holding joint, california marijuana dui defense attorneys
A blood split motion is useful in fighting California Vehicle Code 23152(f), DUI of drugs, as well as in drunk driving cases.

2.2. Using a blood split motion to fight DUI charges

A blood split motion can help uncover “Title 17” violations that can be used to fight California DUI charges. Title 17 of the California Code of Regulations sets forth the procedures law enforcement agencies must follow for DUI chemical tests.

Title 17 regulations that are commonly broken include:

  • Collection of the sample must occur as soon as possible after the alleged offense.
  • Blood must be collected by an authorized technician or medical professional.
  • Enough must be collected to allow a blood split.
  • The blood must not be contaminated with alcohol from other sources (for instance, from alcohol-based disinfectants ).
  • The vial must have sufficient anticoagulant and preservative.13

3. Is there such a thing as a California DUI “breath split”?

California law enforcement agencies are not required to retain breath samples.14 So there is no such thing as a “breath split.”

This means that a "blood split motion" is only a viable DUI defense strategy for drivers who took a blood or urine test.

Police officers are supposed to tell drivers that a breast sample will not be retained for retesting. But even if that happens, the breath test result can still be used against the defendant at trial.15

4. Can a defendant file a "blood split motion" if he/she took a urine test?

Yes. Urine samples (if any) collected in driving under the influence cases must be retained for independent testing. 16 Other requirements for urine tests under Title 17 include:

  • Collection of the sample no sooner than 20 minutes after the defendant has first emptied his bladder.
  • Collection of enough urine so that the sample may be tested at least twice.
  • Retention of the sample for up to one year after it is collected so that a portion can be provided to the defendant upon request (the equivalent of a blood split).17

But note that in most cases (as discussed in Section 1, above), defendants must take a breath or a blood test.

Urine tests are used in DUI cases only when other tests are not available or the defendant is medically unable to take another test.18

urine test california marijuana dui defense lawyers
“Blood split” motions can also be used for retesting DUI urine samples (but not breath samples)

5. How does someone make a California blood split motion?

A "blood split" motion usually begins with the defendant's lawyer informally asking the prosecutor for a portion of the sample. The prosecutor will usually agree to this request. 19

If the prosecutor refuses or fails to turn over the blood or urine split within fifteen days, the court can order the prosecutor to do so.20

The court may also discipline a prosecutor for failing to turn over the split. This discipline may include:

  • Contempt proceedings against the prosecutor,
  • Informing the jury of the delay, or
  • Preventing the prosecutor from using the results of the chemical test at trial.21

What happens if I request a blood split and then don't have it tested?

There is no penalty for obtaining a blood split and not having it tested. But whether or not the sample is retested, the prosecutor may introduce the original result at trial.

6. Examples of how a blood split can be used to help fight a DUI

Below are examples of some positions a defendant may be able to take and how a blood split motion can help.

The defendant had a BAC below 0.08% at the time of driving

Example: Brad has a few drinks with his friends in downtown Barstow. While he is driving home, he is arrested by an officer from the Barstow Police Department. The officer asks him which chemical test he would like and Brad chooses a blood test. The test shows Brad's BAC to be 0.09%.

But Brad's DUI defense attorney requests a blood split. She has the sample sent to a lab for an independent retest. The new test reveals that Brad's BAC was actually 0.07% and that the police lab made a mistake. Brad's lawyer then uses this evidence to persuade the prosecutor to dismiss the charge.

The sample did not contain enough anticoagulant or preservative

Example: Emily meets up with some co-workers for margaritas after work. On the way home, she is pulled over by a California Highway Patrol officer and arrested. She requests a blood test, which shows her BAC to be 0.10%.

Emily's drunk driving attorney requests a blood split. The independent blood test reveals that the blood vial had insufficient preservative. This may have caused the blood to ferment, resulting in a falsely high BAC.

The sample was contaminated

Example: Christine has a glass of champagne at a friend's house in Pasadena to celebrate the friend's promotion. On her way home she runs a red light and weaves into the oncoming lane of traffic. She is stopped by an officer from the Pasadena Police Department.

A preliminary alcohol screening (“PAS”) breath test shows a BAC of .08%, just over the legal limit. While Christine is taking the test, the officer smells marijuana on Christine's breath and clothes. He then notices a baggie of weed on the passenger seat.

The officer arrests Christine for suspected DUI of marijuana and of alcohol. After her arrest, Christine elects to take a breath test. It shows a BAC of .06% (under the legal limit). But because the officer has reason to believe a blood test would show the presence of drugs, the officer requires her to take a blood test as well.22 The test comes back positive for marijuana and opioids.

Christine's lawyer arranges to have the blood sample retested. During the retesting, the independent lab discovers that the blood sample was contaminated with a chemical not found in blood (probably from a disinfectant used on the container).

Christine's lawyer uses this information to negotiate a DUI plea bargain. Christine pleads guilty to a charge of running a red light and escapes with a fine.

The defendant's blood sample was switched with someone else's

Example: After being arrested for a DUI in Oxnard, Miguel submits to a blood test. The test results state that he had a BAC of .10%. But Miguel knows that he only had one drink that night.

Miguel's Ventura County DUI lawyer requests a blood split. Retesting shows a BAC of .04%, well below the legal limit.

Miguel's lawyer investigates and discovers that a technician had made a clerical error. The tech had tested the wrong sample, thinking it was Miguel's. Miguel's DUI defense attorney easily persuades the prosecutor to drop the charges.

7. Can a blood split hurt my defense?

No. It is true that a blood split might return results that do not help the defendant. For instance, the independent testing may confirm the accuracy of the original test. Or it might even show a higher BAC than the police lab reported.

But the new results obtained from the blood split are the defendant's evidence. Unlike the prosecution, the defense does not have to disclose evidence that is favorable to the other side.23

In other words, it might be that the blood split motion does not help the defendant's California DUI defense. But it can't actually hurt it either.

california blood split motions dui defense attorneys
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Charged with DUI in California? Call us for help…

If you or a loved one is in need of help with blood split motions in a California DUI case, we invite you to contact us for a free consultation.

Call us at 855-LAWFIRM or complete the form on this page to speak to an experienced California DUI attorney in your area.

We have local offices in Los Angeles, the San Fernando Valley, Pasadena, Long Beach, Orange County, Ventura, San Bernardino, Rancho Cucamonga, Riverside, San Diego, Sacramento, Oakland, San Francisco, San Jose and throughout California.

We also have offices in Las Vegas and Reno that can bring blood split motions in Nevada DUI cases.

Legal references:

  1. 17 California Code of Regulations (“CCR”) 1219.1(f). 17 CCR 1219.1 provides:

    “(a) Blood samples shall be collected by venipuncture from living individuals as soon as feasible after an alleged offense and processed in compliance with Vehicle Code Section 23158.

    (b) Alcohol or other volatile organic disinfectant shall not be used to clean the skin where a specimen is to be collected. Examples of suitable aqueous disinfectants include: aqueous povidine-iodine (Betadine) or aqueous benzalkonium chloride (zephiran chloride).

    (c) Blood samples from living individuals shall be collected using sterile, dry hypodermic needles and syringes, or using clean, dry vacuum type containers with sterile needles. Reusable equipment, if used, shall not be cleaned with or kept in alcohol or other volatile organic solvents.

    (d) The blood sample shall be deposited into a clean, dry container which is closed with an inert stopper.

    (1) Alcohol or other volatile organic solvent shall not be used to clean the container.

    (2) The blood shall be mixed with an anticoagulant and a preservative.

    (e) When blood samples for forensic alcohol analysis are collected post- mortem, all practical precautions to ensure an uncontaminated sample shall be employed, such as:

    (1) Samples shall be obtained prior to the start of any embalming procedure. Blood samples shall not be collected from the circulatory system effluent during arterial injection of embalming fluid.

    (2) Care shall be taken to avoid contamination by alcohol from the gastrointestinal tract directly or by diffusion. The sample shall be taken from a major vein or the heart.

    (3) Postmortem blood samples shall be mixed with an anticoagulant and preservative.

    (f) In order to allow for analysis by the defendant, the remaining portion of the sample shall be retained for one year after the date of collection.

    (1) In coroner/medical examiner cases, samples shall be retained for at least 90 days after date of collection.

    (2) Whenever a sample is requested by the defendant for analysis and sufficient sample remains, the forensic laboratory, law enforcement agency, or coroner/medical examiner's office in possession of the original sample shall continue such possession, but shall provide the defendant with a portion of the remaining sample in a clean container together with a copy or transcript of the identifying information carried on the original sample container.”

  2. California Vehicle Code 23612(a)(2)(A): “If the person is lawfully arrested for driving under the influence of an alcoholic beverage, the person has the choice of whether the test shall be of his or her blood or breath and the officer shall advise the person that he or she has that choice. If the person arrested either is incapable, or states that he or she is incapable, of completing the chosen test, the person shall submit to the remaining test. If a blood or breath test, or both, are unavailable, then paragraph (2) of subdivision (d) [urine test] applies.”

    See also Vehicle Code 23612(a)(2) (C): “A person who chooses to submit to a breath test may also be requested to submit to a blood test if the officer has reasonable cause to believe that the person was driving under the influence of a drug or the combined influence of an alcoholic beverage and a drug and if the officer has a clear indication that a blood test will reveal evidence of the person being under the influence. The officer shall state in his or her report the facts upon which that belief and that clear indication are based. The officer shall advise the person that he or she is required to submit to an additional test. The person shall submit to and complete a blood test. If the person arrested is incapable of completing the blood test, the person shall submit to and complete a urine test.”

    See also Vehicle Code 23612 (b): “A person who is afflicted with hemophilia is exempt from the blood test required by this section, but shall submit to, and complete, a urine test.”

    See also Vehicle Code 23612 (c): “A person who is afflicted with a heart condition and is using an anticoagulant under the direction of a licensed physician and surgeon is exempt from the blood test required by this section, but shall submit to, and complete, a urine test.”

  3. 17 California CCR 1219.1(f)(2).

  4. Vehicle Code 23612(a)(2)(A), endnote **.

  5. Vehicle Code 23612(a)(2) (C), endnote **.

    See also Vehicle Code 23152(f) – Driving under the influence of drugs.

  6. Vehicle Code 23612 (a) (1) (A): “A person who drives a motor vehicle is deemed to have given his or her consent to chemical testing of his or her blood or breath for the purpose of determining the alcoholic content of his or her blood, if lawfully arrested for an offense allegedly committed in violation of Section 23140, 23152, or 23153. If a blood or breath test, or both, are unavailable, then paragraph (2) of subdivision (d) applies.

    … (d)…(2): “If a blood or breath test is not available under subparagraph (A) of paragraph (1) of subdivision (a), or under subparagraph (A) of paragraph (2) of subdivision (a), or under paragraph (1) of this subdivision, the person shall submit to the remaining test in order to determine the percent, by weight, of alcohol in the person's blood. If both the blood and breath tests are unavailable, the person shall be deemed to have given his or her consent to chemical testing of his or her urine and shall submit to a urine test.”

    See also Vehicle Code 23612 (a)(3): “If the person is lawfully arrested for an offense allegedly committed in violation of Section 23140 [underage DUI], 23152 [DUI], or 23153 [DUI causing injury], and, because of the need for medical treatment, the person is first transported to a medical facility where it is not feasible to administer a particular test of, or to obtain a particular sample of, the person's blood or breath, the person has the choice of those tests, including a urine test, that are available at the facility to which that person has been transported. In that case, the officer shall advise the person of those tests that are available at the medical facility and that the person's choice is limited to those tests that are available.”

  7. Vehicle Code 23612 (a)(5): “A person who is unconscious or otherwise in a condition rendering him or her incapable of refusal is deemed not to have withdrawn his or her consent and a test or tests may be administered whether or not the person is told that his or her failure to submit to, or the noncompletion of, the test or tests will result in the suspension or revocation of his or her privilege to operate a motor vehicle. A person who is dead is deemed not to have withdrawn his or her consent and a test or tests may be administered at the direction of a peace officer.”

  8. Vehicle Code 23612 (b) and (c), endnote **.

  9. See Schmerber v. California (1966) 384 U.S. 757, 86 S.Ct. 1826, 16 L.Ed.2d 908.

  10. See, e.g., Coffey v. Shiamoto (2015) 60 Cal.4th 1198, 185 Cal.Rptr.3d 538,345 P.3d 896.

  11. California Criminal Jury Instructions (CALCRIM) 2110: “The defendant is charged… with driving under the influence of (an alcoholic beverage/ [or] a drug) [or under the combined influence of an alcoholic beverage and a drug] [in violation of Vehicle Code section 23152(a)]. To prove that the defendant is guilty of this crime, the People must prove that:1. The defendant drove a vehicle; AND 2. When (he/she) drove, the defendant was under the influence of(an alcoholic beverage/ [or] a drug) [or under the combined influence of an alcoholic beverage and a drug].”

  12. See, e.g., See National Institute on Drug Abuse, “Effects of marijuana – with and without alcohol – on driving performance,” June 23, 2015.

  13. 17 CCR 1219.1, endnote **.

  14. California v. Trombetta (1984) 467 U.S. 479 (holding the failure to retain breath samples does not violate a defendant's constitutional due process rights).

  15. People v. Mills (1985) 164 Cal.App.3d 652; In re Garinger (1987) 188 Cal.App.3d 1149.

  16. 17 CCR 1219.2: “(a) A urine sample from a living individual shall be a sample collected no sooner than twenty minutes after first voiding the bladder.

    (b) The specimen shall be deposited in a clean, dry container which also contains a preservative.

    (c) In order to allow for analysis by the defendant, the remaining portion of the sample shall be retained for one year after the date of collection.

    (1) Whenever a sample is requested by the defendant for analysis and sufficient sample remains, the forensic laboratory, law enforcement agency, or coroner/medical examiner's office in possession of the original sample shall continue such possession, but shall provide the defendant with a portion of the remaining sample in a clean container together with a copy or transcript of the identifying information carried on the original sample container.

  17. Same. ** 17 CCR 1219.2

  18. Vehicle Code 23612 (b) and (c), endnote **.

  19. California law requires prosecutors to disclose all evidence obtained in a criminal investigation to the defendant(s). See Penal Code 1054.1(c) and Penal Code 1054.5(b).

  20. Penal Code 1054.5(b) PC.

  21. Same. ** Penal Code 1054.5(b) PC

  22. This is allowed by Vehicle Code 23612(a)(2)(C). See endnote 2.

  23. Penal Code 1054.3(a) PC.

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