What Can Affect California DUI Blood Test Results?

The legal limit for DUI in California is a blood alcohol concentration (“BAC”) of .08% or higher. At this BAC level, you are automatically presumed to be impaired by the alcohol in your system. However, you do not have to have a BAC above the legal limit to be charged with driving under the influence.

DUI Blood Testing: How to Challenge the Results in Your DUI Case

California uses a variety of tests to determine the BAC in a driver’s system. Breath and blood tests are the most common chemical tests for DUI. However, numerous conditions and factors could affect California DUI blood test results. If the police charge you with driving under the influence, contact a Southern California DUI lawyer for a free consultation to discuss potential DUI defenses and ways that you can challenge the results of a chemical blood test for BAC levels.

How Does a DUI Blood Test Work?

A qualified technician must perform blood tests in a DUI case. After a DUI arrest, the officer informs you that you must take a chemical test as required by California’s implied consent law (California Vehicle Code §23612). The officer explains that you must provide either a breath sample or a blood sample for chemical testing. Urine tests are only used when breath and blood samples cannot be obtained.

A technician uses an alcohol swab to clean your arm before drawing the blood. Then, the blood is sent to a lab for testing. There are precise rules which must be followed in the DUI Blood Test process.

Are DUI Blood Tests Reliable?

When a blood sample is taken, preserved, and tested correctly, it can be one of the most reliable ways to determine the amount of alcohol in your blood. The test detects the actual chemical content of the blood. Breathalyzers use a formula to estimate the BAC level based on the amount of alcohol on a person’s breath.

What Can Affect a Blood Alcohol Test and Cause a False BAC (Blood Alcohol Concentration) Result?

Blood tests can result in inaccurate results. Many factors could impact the results of a blood alcohol test. Some factors that could result in an inaccurate BAC result from a blood test include:

• The blood sample fermented before performing the BAC test;
• The blood draw was performed too long after the DUI arrest resulting in rising alcohol levels;
• The use of alcohol swabs to clean the areas before drawing blood;
• Certain health conditions of the person being tested;
• Failure to use a vial with the correct amounts of anti-coagulant and preservative;
• Using expired preservatives and/or anti-coagulants; and
• The blood sample was improperly collected and/or stored.

Because factors can result in inaccurate DUI blood test results, it is always in your best interest to discuss your DUI case with a Los Angeles DUI attorney before pleading guilty or accepting a DUI plea bargain.

Frequently Asked Questions About DUI Blood Tests in California

Because law enforcement officers almost always ask the driver for a blood sample, drivers often have questions about a blood draw after a DUI arrest. Below are answers to some of the most common FAQs about California DUI blood tests.

Can I Have a Lawyer Challenge My DUI Blood Test?

Yes, a Southern California DUI attorney can challenge the results of chemical testing for BAC levels. Whether you have grounds to contest the results depends on the facts of your case. Contact an expert DUI lawyer for a free consultation. A judge may exclude test results that could be inaccurate. The state would then need to prove you were intoxicated while driving a motor vehicle.

Can I Have a Different Laboratory Test the Blood Sample?

Title 17 of the California Code of Regulations provides the procedures for drawing, testing, and storing blood samples for DUI cases to comply with California Vehicle Code §23158.

In 17 CCR §1219.1, the regulations require that technicians collect a sufficient blood sample to provide for multiple tests. Individuals have up to one year after collecting their blood to request a sample for independent testing.

If you hire a defense attorney, they should request a portion of your blood to have it retested at an independent laboratory. If the prosecution refuses the request, the attorney files a “blood split motion” with the court asking for an order compelling the prosecutor to provide a sample of the blood for independent testing.

What if the Technician Used an Alcohol Swab Before the Blood Test? Can Alcohol Swab Affect Blood Alcohol Test?

Using an alcohol swab to clean the areas before drawing blood can impact the results of the test. Technicians violate Title 17 regulations if they use alcohol or a similar product to clean the area before a blood draw. Instead, technicians must use a non-alcoholic disinfectant to prep the skin for drawing blood.

How Long Does Blood Work Take to Come Back for Alcohol?

Several factors impact the timeline for blood work to come back from a lab. The lab’s backlog of tests is often the deciding factor in how long it takes to get results. It typically takes four to eight weeks to receive the results of a BAC test. However, it could take much longer if there are problems with the sample or the lab has a backlog of samples to test. The same is true with private laboratories that a California DUI defense lawyer might use to perform independent testing of DUI blood samples.

The results of breath tests are instant. However, officers do not preserve a sample of your breath. Therefore, there is no way to perform an independent test on the breath sample you provided after your DUI arrest.

Is Refusing a Blood Test a Good Idea or a Bad Idea? What Happens if I Refuse Chemical Testing?

It depends on the situation. Most people do not refuse a chemical test because there are penalties for refusing testing after a lawful DUI arrest. However, many drivers choose a breath test because it is less invasive than a blood test. Unfortunately, a breath test has a higher chance of being inaccurate than blood testing.

Why Is Attacking the Blood Test Results Such a Big Deal?

California Vehicle Code §23152 makes it illegal to drive with a blood alcohol content above the legal limit of .08%. It also makes it unlawful to operate a motor vehicle under the influence of alcohol or drugs. It is much easier for the state to prove you are guilty of drunk driving when it has test results showing your BAC exceeded the limits set by law.

Without the results of a blood test, the prosecutor must prove that you were “impaired” by alcohol or drugs in your system. Being impaired means you cannot operate the vehicle with the same level of care as a reasonably cautious sober person. Because impairment is a subjective conclusion, obtaining a DUI conviction without proof that the person’s BAC was above the legal limit can be more challenging.

Can I Still Fight the Blood Test if I Was Drinking or Using Drugs?

It is common for California DUI lawyers to challenge blood tests even if their client was drinking or using drugs. Again, for DUI charges, the state must prove your guilt beyond a reasonable doubt. Officers must follow regulations and statutes for chemical testing after a DUI arrest. Any slight error or deviation could be grounds for calling into question the results of a BAC test. The case might come down to expert witnesses testifying during a trial with differing opinions about whether the test results were accurate or inaccurate. Jurors would have to decide what to accept as fact.

When Is a DUI Blood Test Required in California Law?

Drivers are required to provide samples for testing after they are lawfully arrested for driving under the influence or DUI per se. Generally, the driver must choose between providing a blood or breath sample. However, there are exceptions to the rule.

For example, an officer can require a blood test if there is reasonable suspicion that the driver is under the influence of drugs. Also, the officer may require a blood sample when the driver is unconscious or deceased. Drivers taken to medical facilities that do not have breath testing equipment might be required to provide a blood sample.

Is It Better to Take a DUI Blood Test or Breath Test?

Breath tests are less invasive and faster, so many drivers choose a breathalyzer test. They blow into the mouthpiece to provide the breath sample. However, not everyone can provide a deep lung air sample required for a breathalyzer test’s accuracy. They might be unconscious or have a health condition that prevents them from breathing deeply.

Other drivers prefer a DUI blood test because they know that it measures the alcohol in their system instead of estimating BAC levels. Partition ratios are crucial components of the breathalyzer test, and the ratios are set by law. However, a driver may have a different partition ratio, which could impact the test results. Furthermore, breath samples cannot be preserved for retesting like blood samples.

What are the Title 17 Regulations?

Title 17 regulations refer to Title 17 of the California Code of Regulations. It provides detailed rules and procedures for collecting, testing, and storing chemical test samples. Violations of any of the provisions by officers, technicians, or labs could result in inaccurate test results. It could also give the court grounds to make the DUI test results inadmissible in court.

Are Blood Test Results Presumed to Be Valid?

There is a presumption that the results of a blood-alcohol test are accurate. In other words, the defendant has the burden of proving that the results are inaccurate. Title 17 procedures are often used to challenge the results of a test. However, a judge could find that the defendant’s constitutional rights were not violated. If so, the judge may allow the test results to be used as evidence during the trial even though there were violations of Title 17 regulations.

Forced Blood Draws – Can the Police Force a Person to Take a Blood Test?

There are very few cases where a person’s blood can be taken without a warrant. In the case of Birchfield v. North Dakota, the United States Supreme Court ruled that a warrantless breath test did not violate a person’s Fourth Amendment rights. However, warrantless blood tests do.

The case only applies when a state makes it a crime to refuse a blood test after a DUI arrest. California does not criminalize refusing a chemical test. Instead, the California Department of Motor Vehicles (“DMV”) administratively suspends a person’s driver’s license. The person only faces an enhanced penalty for test refusal if convicted of drunk driving.

A judge may issue a warrant for a blood sample resulting in a forced blood draw. A person can be physically forced to provide a blood sample if the police have a warrant.

Should I Hire a Lawyer to Dispute My Blood Test Results? 

If the police arrest you for driving under the influence, it is always in your best interest to call a Southern California DUI attorney for a free consultation. There could be one or more valid grounds for challenging the blood test results that could result in a dismissal or acquittal. You won’t know until you talk with an experienced defense lawyer.

Talk To A DUI Defense Attorney

You may have defenses to felony charges or may be able to get them reduced to a misdemeanor or “wet reckless” charges. An experienced attorney can evaluate your case and discuss your options with you. A lawyer serving DUI clients will often offer a free no obligation consultation and everything discussed is protected by the attorney client relationship.

Schedule a free consultation with one of our expert California DUI attorneys here.

Sources:

https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=VEH&sectionNum=23612

https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=VEH&sectionNum=23158.

https://govt.westlaw.com/calregs/Document/I9F4B2C835A2011EC8227000D3A7C4BC3?viewType=FullText&originationContext=documenttoc&transitionType=CategoryPageItem&contextData=(sc.Default)

https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?sectionNum=23152.&lawCode=VEH

https://www.oyez.org/cases/2015/14-1468

The Only 3 Effective DUI Field Tests

Police officers use field sobriety tests (“FSTs”) when they stop a driver suspected of being under the influence of drugs and/or alcohol. The three standardized field sobriety tests (“SFSTs”) are considered the most reliable FSTs and the tests recommended by the National Highway Traffic Safety Administration for use by law enforcement agencies. However, police officers also use non-standardized field sobriety tests. Unfortunately, all tests have potential issues that can make the results unreliable.

The Purpose and Types of DUI Field Sobriety Tests

How do police officers use field sobriety tests during DUI investigations in California?

California uses the three standardized field sobriety tests to conduct DUI investigations during traffic stops. The purpose of conducting the tests is to determine whether a driver is impaired. The tests also serve to provide probable cause for a DUI arrest. A police officer must have probable cause to believe the person is intoxicated before making a lawful DUI arrest.

Three tests were chosen as standardized field sobriety tests. Each test has specific instructions and procedures for giving the test to a driver. Any deviation from the procedures could make the test results inaccurate and unreliable. Those three tests are: (1) Horizontal Gaze Nystagmus Test (“HGN”); (2) Walk and Turn Test (“WAT”); and (3) One-Leg Stand Test (“OLS”).

Horizontal Gaze Nystagmus Test (“HGN”)

The Horizontal Gaze Nystagmus Test checks for involuntary “eye jerking” or nystagmus, which occurs when a person looks to the side without turning their head. The severity of the “jerking” increases when a person is intoxicated. An HGN test can also detect when a person has consumed certain prescription medications and illegal drugs.

The police officer performs the test by instructing the person to focus on a stimulus, which is usually a small object, finger, or pen. The officer moves the stimulus horizontally across the person’s line of sight about a foot to 15 inches away. As the driver’s eye follows the object, the police officer watches for signs of increased nystagmus including:

• Inability to follow the object smoothly;
• Distinct jerking at maximum deviation; and
• Substantial eye jerking within a minimum of 45 degrees from the center.

The officer looks for the signs in each eye, checking for six total signs of increased nystagmus.

Walk and Turn Test (“WAT”)

The Walk and Turn Test is the test most people are familiar with due to its depiction in movies and television. During the WAT, a police officer instructs the driver to take nine steps along a straight line, turn around, and then take nine steps back to the starting point. The steps must be heel-to-toe steps.  The officer instructs the driver to count the steps out loud as they take each step. The officer watches for eight indications that the person might be impaired:

• Inability to balance while listening to instructions;
• Making an improper turn;
• Beginning to walk before the officer instructs the person to begin the test;
• Taking the wrong number of steps;
• Stopping to regain balance while walking;
• Stepping out of line;
• Failing to touch the heels to the toes; and
• Using the arms for balancing.

The standardized instructions state that if the person displays at least two of the eight indicators, they fail the walk-and-turn test.

One-Leg Stand Test (“OLS”)

The police officer instructs the person to stand still and lift one foot off the ground about six inches. The officer instructs the person to count by one until the officer tells them to stop while holding their foot off the ground. The standardized instructions state the officer should time the suspect and stop them in 30 seconds. The officer looks for four indicators of impairment:

• Hopping during the test;
• Repeatedly swaying during the test;
• Putting their foot down one or more times; and
• Using the arms to maintain balance.

The standardized instructions state that committing two or more of the four indicators means the person failed the one-leg stand test.

Field Sobriety Tests: Potential Problems and Challenges

Even though the above tests are widely considered reliable indicators of driving under the influence, there are many problems with the tests. Critics cite issues with the accuracy and reliability of test results. They also question environmental factors and the actions of police officers that could result in flawed test results.

What Do the Tests Mean if You Fail?

The police officer should refer to their FSTs training to determine if the person “failed” a field sobriety test. As indicated above, specific instructions in the training materials indicate when a person has “failed” the test.

If the officer decides that you failed one or more of the FSTs, the officer will likely state they have probable cause for a DUI arrest. The officer may then ask the driver to take a preliminary alcohol screening (“PAS”) test, which is generally a field breathalyzer machine. A BAC (“blood alcohol content”) level on the breathalyzer gives the officer additional probable cause to make an arrest for DUI.

After a lawful DUI arrest, California’s implied consent laws require individuals to take a chemical test. The police officer should ask the person whether they want to provide a sample for a breath test or a blood test for chemical testing. Urine tests are only used when blood and breath tests are unavailable.

Field Sobriety Tests: Accuracy, Limitations, and Criticism

There are limits to using field sobriety tests during a DUI stop. There are also questions regarding the accuracy of field sobriety tests. Some of the issues that DUI defense attorneys raise regarding the use of FSTs in DUI cases include:

• The accuracy of field sobriety tests;
• Failing to provide clear and correct instructions;
• Environmental factors;
• Medical conditions;
• Being nervous &/or scared; and
• The subjectivity of SFSTs.

The Accuracy of Field Sobriety Tests

Several studies have been conducted on the accuracy of FSTs in determining whether a driver is impaired by alcohol and/or drugs. The NHTSA Instructor Guide for the tests explains that three studies were conducted between 1995 and 1998. The studies were conducted in San Diego, Florida, and Colorado. Each study resulted in different conclusions regarding the accuracy of FSTs.

The Instructor Manual states that officers should use the San Diego Field Validation Study when testifying in court. That study indicated the following accuracy rates:

• HGN tests were 88% accurate;
• OLS tests were 83% accurate; and
• WAT tests were 79% accurate.

Even though the NHTSA claims that the study results provide clear evidence of the validity of standardized field sobriety tests, California DUI defense lawyers disagree. First, these tests are not 100% accurate. Moreover, other scientific tests have shown that the accuracy of these tests is questionable.

One study used sober individuals to perform standardized FSTs. After watching videos of people taking the tests, police officers believed that a significantly larger number of the people were impaired. Another study concluded that the HGN test has a high baseline error and varied greatly depending on whether the person’s BAC level was rising or falling. In 52 videos of DUI arrests, the study authors concluded the HGN test was incorrectly administered 51 times.

Additionally, other factors make the accuracy and validity of the tests questionable.

Failing to Provide Clear and Correct Instructions

The police officer administering the SFSTs must follow the exact procedures for giving the test to a driver. Deviation from the procedures could result in inaccurate results. However, suppose there is no body camera footage, other video footage, or audio evidence that the officer gave the person clear and correct instructions. In that case, there is no way to know if the officer purposefully or unintentionally caused the person to “fail” the field sobriety test.

Environmental Factors

Numerous environmental factors could invalidate the results of standardized field sobriety tests. For example, the officer should conduct the tests on a level, paved surface. Otherwise, the person may stumble or lose their balance because of the ground, but not because they are impaired by alcohol. Another example is conducting the HGN test with bright lights shining in the person’s eyes from the sun or oncoming traffic. The lights could cause unreliable results.

Medical Conditions

Another problem to consider is the person’s health condition. A person may have a medical condition that prevents them from passing the test even though they are sober. In addition, a person’s age could cause them to perform poorly on a test even though they are perfectly capable of operating the motor vehicle safely. Physical limitations may prevent someone from “passing” the one-leg stand test or the walk-and-turn test.

Some medications could cause a person to exhibit signs of intoxication even though they are sober and not impaired. For example, some medications for seizures can cause increased nystagmus even though the person is sober. In addition, there are dozens of other possible causes of nystagmus, including hypertension, eye strain, glaucoma, and consuming excessive amounts of caffeine.

Being Nervous and Scared

Merely being nervous about being pulled over and scared of being arrested could cause someone to perform poorly on SFSTs.

SFSTs are Subjective

Whether you fail or pass a sobriety test depends upon the officer’s interpretation of your performance during the tests. In other words, one officer might conclude you were intoxicated and arrest you for drunk driving. Another police officer might conclude that you are not impaired and release you without an arrest. A study conducted using police officers, bartenders, and university community members found that the group had less than a 25% accuracy rate when correctly determining how drunk a person was after observing the targets for several minutes. Furthermore, the accuracy of the ratings worsened as the targets’ level of intoxication increased.

If a police officer has some bias against the person, the officer might unethically or unconsciously interpret the results in favor of probable cause and an arrest. For example, a driver was rude and obnoxious when the officer made the initial traffic stop. The person was critical and uncooperative. In that case, the officer might decide that the person is drunk and make the arrest, even though the results of the SFSTs were borderline.

Non-Standard Field Sobriety Tests

Some jurisdictions also use non-standardized field sobriety tests to determine impairment to support probable cause for a DUI arrest. Police officers claim the non-standard FSTs are reliable because they require the person to utilize split focus and dexterity, which is difficult to do if the person is drunk or drugged. However, these non-standardized tests are unreliable and highly subjective. Some non-standard field sobriety tests used by police officers include:

• Romberg Balance Test – Closing the eyes and tipping the head backward while standing with the feet together, estimating when 30 seconds have passed, and then saying “stop” to the officer.
• Finger-to-Nose Test – Closing the eyes and touching a finger to the tip of the nose.
• ABC Test – Reciting the alphabet forwards or backward.
• Finger-Tap Test – Tap a finger to your thumb as fast as possible with an opening between taps as wide as possible.
• Numbers Backward Test – Counting backward.
• Stand and Gaze Test – Standing and leaning so that the person gazes at the sky while holding their arms to their sides.
• Hand Pat Test – Extend an arm out with the palm facing up and out. Place the other hand on top of the raised palm facing down. Rotate the hands 180 degrees to pat the bottom hand with the back of the other hand before rotating and doing it again while counting “one” and “two” each time.

The NHTSA does not recognize these tests as reliable indicators of whether a person is impaired by alcohol and/or drugs. A skilled California DUI defense attorney will challenge these test results in court. Challenging non-standard field sobriety tests is easier because they are not widely accepted as accurate indicators of intoxication or impairment.

Field Sobriety Test Refusals – Drivers Aren’t Required to Participate in Field Sobriety Tests

No California law punishes a person for refusing to take a field sobriety test. However, a police officer will not tell you this detail. Instead, the officer will only ask you to perform the tests without indicating that you may refuse the test without punishment. Understanding your right to refuse to take a field sobriety test is essential because sober people can fail the tests.

However, there is a difference between field sobriety tests and chemical tests for BAC levels. California’s implied consent laws require drivers to submit to a chemical test of their blood or breath after a lawful DUI arrest. Refusing a chemical test after a DUI arrest results in an administrative driver’s license suspension by the California Department of Motor Vehicles (“DMV”). Your driving privileges are suspended for one year for a first-time refusal of a chemical test. A second refusal within ten years results in a two-year revocation of your driver’s license.

However, if you are under 21 years old or on probation, refusing a chemical test after a DUI arrest of a preliminary alcohol screening (“PAS”) test after being detained results in a one-year driver’s license suspension for the first refusal and two-year revocation for a second refusal within ten years.

California Vehicle Code §23612 states that an officer must advise you that refusing the chemical test could result in a suspension of your driving privileges. Your California DUI attorney might be able to successfully argue against the DMV administrative license suspension if the officer failed to provide the required advisements.

How Field Sobriety Test Results Are Used in Court & Challenging FSTs Results in California

The prosecution uses the results from field sobriety tests in court in several ways. First, the prosecutor may use the FSTs to support the finding that the police officer had probable cause to arrest you for driving under the influence.

If you are charged with driving under the influence, the prosecutor uses field sobriety tests to support the allegation that you were too impaired to drive. This situation often occurs when the driver refuses to take a chemical test. The state does not have evidence of the BAC level at the time of the arrest. Therefore, it must prove that your ability to operate the vehicle was impaired.

When you are charged with DUI per se, the state has BAC test results showing that you were driving with a BAC over the legal limit. Generally, the BAC test results are sufficient to prove the state’s case if there is no valid DUI defense to convince the jury you were not drunk or under the influence of drugs. However, a prosecutor might use the FSTs results as additional evidence you were drinking and driving.

A skilled California DUI lawyer challenges the results of standardized FSTs in court. The attorney might challenge the results in one of several ways including:

• Challenging the reliability of the tests based on data showing a considerable margin for error. The attorney might hire an expert witness to provide testimony regarding the accuracy of the test.
• Providing evidence that the law enforcement officer failed to administer the standard FSTs according to the procedures in the NHTSA manual.
• Offering evidence proving that the test results were negatively impacted by a medical condition, legal prescription medications, or environmental factors.
• Your clothing, lack of sleep, muscle fatigue, advanced age, injuries, weight, or other extraneous conditions caused poor performance on the FSTs.
• The officer administered non-standardized field sobriety tests.

There could be other challenges and DUI defenses in your case. Schedule a free consultation to talk with a DUI lawyer about potential defenses to drunk driving charges.

Talk to a California DUI Defense Attorney

Fighting DUI charges begins with hiring an experienced DUI defense attorney. Contact a criminal defense lawyer for a free consultation to discuss your case. Most attorneys offer a free consultation so that you can get answers to your questions about DUI defense and your legal rights to make an informed decision about how you want to proceed with your DUI case.

Schedule a free consultation with one of our expert California DUI attorneys here.

Interested in this topic or want to learn more about DUIs in California? Check out our blog, which is updated regularly!

Sources:

https://www.ojp.gov/ncjrs/virtual-library/abstracts/standardized-field-sobriety-testing

https://www.nhtsa.gov/sites/nhtsa.gov/files/documents/sfst_ig_refresher_manual.pdf

https://pubmed.ncbi.nlm.nih.gov/7991338/

https://pubmed.ncbi.nlm.nih.gov/11393940/

https://psycnet.apa.org/record/1984-12497-001

https://www.dmv.ca.gov/portal/driver-education-and-safety/dmv-safety-guidelines-actions/driving-under-the-influence/

https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=VEH&sectionNum=23612

You might not realize it, but if you drive after using mouthwash or a breath freshening spray, you could actually face DUI charges in California. Some of these substances contain alcohol, which will trigger a false positive result on a breath test device, also called a breathalyzer.

Raising the defense of mouthwash or breath spray in a DUI case is a daunting matter, best attempted by an experienced California DUI attorney. This defense, also called mouth alcohol defense, can be successful in the right circumstances.

Can You Get a DUI From Mouthwash or Breath Spray?

Sometimes, people can cause higher results of a breathalyzer blood alcohol concentration (“BAC”) reading through their use of a breath spray or mouthwash immediately before taking the breathalyzer test. This situation could arise in the following hypothetical situation: Let’s say a person was pulled over by the police, but they had had a drink at dinner and worried their breath may have smelled like alcohol. In their preoccupation of this thought, the person then used a breath spray or mouthwash to try to mask the smell of alcohol on their breath.

However, it’s important to note that the police are aware that people may try to cover up the scent of alcoholic beverages by using mouthwash or breath fresheners, so the person’s actions in our above hypothetical may have only increased their suspicion of the presence of alcohol.

When alcohol is swished around in the mouth, a breathalyzer will detect the presence of alcohol. However, it will not be able to distinguish whether that alcohol is scotch or Listerine. In fact, people who struggle with alcohol addiction often refrain from using breath freshening sprays or mouthwash because the amount of alcohol in these products could cause a recovering alcoholic to “fall off the wagon.”

In addition to mouthwash and breath sprays, over the counter remedies such as cough syrups, NyQuil, or other cold medications also contain enough alcohol to generate a false positive reading by a breathalyzer. Some naturopathic or homeopathic compounds have an alcohol base that can trip up a chemical breath test device. Even cooking extracts like vanilla or almond extract have an alcohol base.

How a Breath Test Works

Duke University describes how a DUI breath test device like a breathalyzer works. There are many different types of breath analyzers on the market today, which all function in generally the same way as the original breathalyzer.

The chemical testing device is about the size and shape of a cell phone, with two chambers inside the testing device. These chambers contain a reddish-orange liquid, called potassium dichromate. The person suspected of being intoxicated exhales into one of the test chambers through a mouthpiece. Any alcohol in the breath sample will react to the potassium dichromate solution and turn green. The level of alcohol in the breath sample will directly affect the degree of color change. The more ethanol vapor present in the breath sample from the suspect, the more that green color will appear on the photocell. 

The second chamber in the device contains the potassium dichromate solution separated from the breath sample. The chemical solution in the second chamber should not react. The difference in the degree of colors in the two chambers creates an electrical current that the device then converts into a quantitative value that represents the blood alcohol concentration of the breath sample.

Can Mouthwash Cause Breathalyzer Test Failure?

Yes; mouthwash can cause a breathalyzer test failure. As mentioned above, you can actually blow a higher BAC number if you recently used mouthwash than if you had not swished this product around in your mouth. Whether you were stone cold sober and simply used mouthwash as part of your oral hygiene routine or you tried to cover up the smell of alcohol on your breath when you saw the flashing police car lights behind you after you had a few drinks, you could fail a breathalyzer test because of mouthwash. 

Many types of mouthwash contain alcohol, which can leave a highly concentrated alcohol vapor in your mouth. This “mouth alcohol” will get detected by a chemical breath test device, meaning you could appear to have been drinking even when you were not. Also, a BAC that is below the legal limit could get boosted to a high enough number to get you arrested and charged with a DUI because of the additional alcohol present in your mouth from mouthwash.

How Does Mouthwash Affect Breathalyzer Results?

Breath test chemical analyzers do not know the difference between alcohol from mouthwash and alcohol from beer, wine, or spirits. Even though your breath sample is supposed to be “deep lung air,” the sample has to pass through your mouth to get into the chemical analysis device. Some of this specimen will be alcohol vapor from inside your mouth, rather than deep in your lungs, which can impact the results of the test.

What Is Mouth Alcohol and How Does It Affect My DUI Case?

Mouth alcohol is the presence of alcohol vapor created by swishing alcohol containing substances around in your mouth. Although this article focuses largely on breath fresheners such as mouthwash, mouthwash is not the only product that can cause mouth alcohol. Swallowing liquid cold or flu medicines that contain alcohol can also create mouth alcohol.

Alcolock, a manufacturer of ignition interlocking devices (“IIDs”) says that the alcohol content of some mouthwashes is surprisingly high. For example:

• The original formula Listerine has an alcohol content of 26.9%;
• The mint flavors of Listerine have nearly 22% alcohol;
• The alcohol content of Scope is 18.9%; and
• Cepacol contains 14% alcohol.

In comparison, wine contains 12% alcohol and beer contains 3 to 7% alcohol. According to Alcolock, mouthwash can cause a person to fail an interlock test.

They warn that, in addition to mouthwash, breath sprays, cold and allergy medications, and cough syrup, your breath could contain mouth alcohol from vinegar, some energy drinks, and “non-alcoholic” beer. Please note that non-alcoholic beers are not necessarily alcohol-free. Rather, their alcohol content is below the level to qualify as an alcoholic beverage. 

How Long Does Mouth Alcohol Last?

Because the body can usually metabolize the equivalent of one alcoholic beverage an hour as a general rule, people often think that alcohol is not detectable after that time. On the contrary, alcohol detection testing devices can discover the presence of alcohol in your system for 6 to 72 hours, depending on the type of testing performed. 

For example, according to American Addiction Centers, alcohol can remain in a person’s system:

• Up to six hours in the blood;
• For 12 to 24 hours in the breath or saliva;
• For 12 to 24 hours in the urine when older detection methods get used and 72 hours or longer with the most current testing methodology; and
• As long as 90 days in the hair.

Some sources suggest that mouth alcohol dissipates quickly and that you can swish water around in your mouth and ask the officer to wait for 15 or 20 minutes and then perform a retest. However, the likelihood of receiving a significantly different result on the second test will depend on many factors, like the quality of chemical breath testing device and whether you have had any alcohol to drink in the past 24 hours. 

How Does Individual Health History Affect Mouth Alcohol?

A person with certain gastrointestinal diseases like acid reflux disease, a hiatal hernia, or GERD might fail a breathalyzer test because of mouth alcohol. These medical conditions can cause alcohol vapors to travel back up the esophagus and into the mouth, where they can get detected by a breathalyzer.

Additionally, a person who wears dentures or an orthodontic retainer could have residual mouth alcohol which was trapped by their dental appliance. When they blow hard into the chemical breath testing device, the trapped mouth alcohol could get released into their breath sample and cause a false positive.

What Happens if I Fail a Police Breathalyzer Because of Mouthwash?

If you failed a police breathalyzer and you think it was because of mouthwash, you should seek the help of an experienced drunk driving attorney immediately. Your defense attorney can offer guidance on how to prove that the mouthwash caused the false positive result.

Can Mouth Alcohol Be Used as a DUI Defense?

Yes, the presence of mouth alcohol can be used as a DUI defense if it caused you to have an inaccurate or misleading BAC reading on a breathalyzer.

Frequently Asked Questions About Mouth Alcohol and Mouthwash

People who have been charged with a DUI based on a breathalyzer test which they believe produced inaccurate results due to mouth alcohol from liquids such as mouthwash have many questions. Some of the more common things they want to know are: 

Can Mouthwash Get You a DUI?

Yes, mouthwash can get you convicted of the offense of driving while under the influence of alcohol. If you do not successfully challenge the breathalyzer results, you can face a conviction for a crime you did not commit.

Can Mouthwash Cause You to Fail a Breathalyzer?

Yes, mouthwash that contains alcohol can make you fail a breathalyzer test. Breath testing devices do not distinguish between the alcohol in mouthwash and “drinking” alcohol.

Can Mouthwash Make You Test Positive for Alcohol?

Yes, mouthwash can make you test positive for alcohol on a breathalyzer test if the type of mouthwash you used contains alcohol.

How Much Do Mouthwashes Affect Breathalyzers?

Mouthwashes can greatly affect breathalyzers. If you recently used a mouthwash with alcohol as one of its ingredients, a breathalyzer could have a false positive rating.

Does Mouthwash Affect Ignition Interlock Devices (“IIDs”)?

Absolutely. Mouthwash can cause you to accidentally fail an ignition interlock device test if the mouthwash contains alcohol. Makers of IIDs urge people who use interlock devices to refrain from using mouthwash or other everyday products that contain alcohol for as long as they have their ignition interlock device installed. There are alcohol-free brands of mouthwash that can provide the sensation of fresh breath without causing a false positive on an IID. 

Responding the Right Way to an Unfair Breathalyzer Result

Your defense attorney can handle the response to an unfair breathalyzer result in your DUI case. The precise steps they will take to fight the criminal charges will depend on the particular facts of your situation.

We offer a free consultation to talk to you about whether false readings on a breath machine from mouthwash, cough drops, dental work, or some other cause could be used as a mouth alcohol defense. If you’d like to learn more about applying this defense to your case, you can speak a DUI Defense attorney today by reaching out to us here.

Sources:

https://sites.duke.edu/apep/module-4-alcohol-and-the-breathalyzer-test/content-how-does-the-breathalyzer-work/

https://alcolockusa.com/faq/can-mouthwash-cause-a-failed-interlock/

https://americanaddictioncenters.org/alcoholism-treatment/how-long-in-system

DUI breath tests are standard tools used to prove someone was driving under the influence of alcohol in California. However, breathalyzer tests are not always accurate. Furthermore, the breathalyzer does not measure the amount of alcohol in your bloodstream, so there is the opportunity to contest the accuracy with partition ratios.

How Does a Breath Test Work for a California DUI?

Police officers use two types of breath tests to determine if a driver was intoxicated while driving. First, the roadside preliminary alcohol screening (PAS) test is a roadside breathalyzer. It is given during a DUI stop and investigation.

You can refuse the PAS test without penalty unless you are under 21 years of age or on DUI probation. You can also refuse to take a cheek swab or perform the field sobriety tests too. However, you cannot refuse the second breath test without penalty.

The second breath test is a post-arrest evidentiary breath test. You cannot refuse a chemical BAC test after your arrest without penalty. These are evidentiary tests, meaning the state can use the results in court. 

Most drivers choose between the post-arrest breath test and the blood test. However, the person may be required to take a blood test if the officers believe they have drugs in their system (DUID), they cannot blow hard enough for the breath test, or the driver is unconscious or in a medical facility where a breath test is not available. 

How Does a Breathalyzer Test Work?

Understanding how to challenge the results of a breath alcohol test using partition ratios in California helps to understand how breath tests work. DUI breath tests do not measure the blood alcohol level in your bloodstream. Instead, they measure the amount of alcohol in the deep lung air.

Deep lung air comes from the alveoli located deep within the lungs. Tiny blood vessels surround the alveoli. The blood vessels allow oxygen to pass from the lungs into the bloodstream and allow carbon dioxide and other substances, like alcohol, to pass from the blood to the alveoli. 

The alcohol concentration is highest in the alveoli. Therefore, an evidentiary breath test uses the air from this area to test for alcohol in your system. However, you must blow very hard to get the air from the alveoli into the machine. Some individuals may not be able to blow hard enough and might need a blood test.

How Can the Partition Ratio Lead to Inaccurate BAC Levels?

Since the breath test measures the amount of alcohol in your lungs, the results must be converted to a rough equivalent of a BAC. The mathematical conversion is known as the partition ratio. 

California laws set the partition ratio for breath-testing at 2,100 to 1. In other words, the amount of alcohol in 2,100 milliliters of breath is equal to the amount of alcohol in 1 milliliter of blood.

However, everyone’s body is unique. Your partition ratio may differ from the fixed partition rate because everyone’s lungs absorb the alcohol at a different rate. 

How Does the Partition Ratio Impact a DUI Case?

Under California Vehicle Code §23152, it is unlawful for you to operate a motor vehicle if:

• Your BAC is .08% or higher (per se charge) OR
• You are under the influence of any alcoholic beverage (generic dui charge)

A per se DUI is where the person’s BAC is .08% or higher. The law presumes that you were too drunk to drive if you have a BAC over the legal limit. Therefore, if your breath test shows a BAC of .08% or higher, you are presumed to be too impaired to operate a motor vehicle.

However, if your BAC is below the legal limit, you are charged with a generic DUI. The prosecution must show that the alcohol in your system actually impaired your ability to operate the motor vehicle safely. In cases with BAC close to the legal limit, the prosecutor might get a conviction if there is other evidence the driver was intoxicated. 

On the other hand, if the person’s partition rate is not 2,100:1, the person’s BAC level might be much lower than the level alleged by the prosecution. If so, the person may not have been impaired by alcohol when they were pulled over for a DUI stop.

Challenging the Results of a BAC Level Using Partition Ratios

In July 2009, the California Supreme Court decided an important case that changed how some people defend themselves against the generic DUI charge. The decision in People v. McNeal allows a defendant to contest the accuracy of a breath test by submitting evidence their partition ratios are not equal to the ratio set by law. Defendants may also challenge the results by offering evidence proving the variance of partition ratios among the general public. 

In a borderline BAC case, offering evidence that the defendant’s individual partition ratio is different from the state’s ratio could create reasonable doubt for the jury. Especially when there is no substantial evidence other than the breath test that proves the defendant was intoxicated while driving.

If your DUI case relies on the results of a breath test, talk with a California DUI defense lawyer before accepting a plea deal. You may have grounds for challenging the results to prove you were not drunk while driving. 

Other Ways to Challenge an Evidentiary Breath Test in a DUI Case

In addition to challenging the accuracy of the breath test results based on partition ratios, there are other ways to attack a breath test. For example, the California Code of Regulations Title 17 sets the rules for DUI chemical testing procedures. As a result, the samples could be invalid when labs and law enforcement officers do not follow these rules.

There are many rules under Title 17 for performing a breathalyzer test after a DUI arrest. Some important rules include:

• The device must be calibrated every 150 uses or ten days, whichever comes first
• The person giving the breathalyzer test must be trained to use the specific device
• The DUI breathalyzer device must be in good working order
• Air from deep within the lungs must be collected to perform the test
• The driver must be watched continuously for 15 minutes before the DUI breath test to ensure they did not eat, drink, or put anything in their mouth, smoke, vomit, burp, or regurgitate
• The lab must keep detailed records of the personnel, equipment calibration, and test results
• Two breath samples do not differ by more than 0.02 grams per 100 milliliters of blood must be obtained

Violation of any of the above Title 17 rules could result in inaccurate BAC levels that are not as high as they appear. A DUI defense lawyer reviews the testing procedures and records to determine if the lab or law enforcement agency made errors that could support a challenge to the breath test results.

Medical Conditions and Other Factors Could Result in Incorrect BAC Breath Test Results

In addition to problems with the machine and errors made by law enforcement agents or lab workers, a person’s medical conditions could affect the accuracy of a breath test. Specific health conditions can result in falsely high BAC levels. 

Examples of medical conditions or other factors that could affect the BAC results from a breathalyzer include: 

• Diabetes
• Gastrointestinal reflux disease (GERD)
• Low carb/high protein diets
• Residual mouth alcohol
• Inhaling acetone and other volatile chemicals
• Rising blood alcohol levels
• Medication, food, or mouthwash caused a false high
• Dentures caused the alcohol to pool in the mouth

There are many ways to challenge an evidentiary breath test. It is worthwhile, especially in cases where the BAC level may be just below the legal limit. Challenging the accuracy of the test can help jurors accept your argument that you might have had some alcohol, but you were not impaired to drive.

What Should I Do After a DUI Arrest in California?

Do not panic. You have not been convicted of driving under the influence. However, the matter is extremely serious. The punishments for a DUI conviction in California can be harsh.

Therefore, do not talk to the police. The police officers and the prosecutor already believe you are guilty. Any information you give them only makes their case against you stronger.

Instead, remain quiet until you speak with a California DUI defense attorney. Your attorney discusses the facts of your case, your legal rights, potential defenses, and the best options you have for fighting the DUI charges. 

You might want to fight the drunk driving charges based on your attorney’s advice. You might have a solid challenge to the evidentiary breath test results based on partition ratios or errors regarding the test. 

If not, your attorney works to negotiate the best plea bargain possible. A prosecutor may be willing to work out a better deal with an attorney than directly with you. 

The prosecutor knows if a deal is not struck, the case goes to trial. That might not be in the prosecutor’s best interest. Furthermore, the prosecutor has hundreds of cases to handle. They want a win, not a hard fight for a potential acquittal.

Ensure you know your legal rights after a DUI arrest to reduce the chance of jail time and other penalties.

Law enforcement officers rely heavily on field sobriety tests (FSTs) in California to determine if a driver is impaired by alcohol or drugs during a traffic stop. The FSTs may be the only “evidence” an officer collects during a DUI investigation to justify an arrest for driving under the influence. The theory is that poor performance on field sobriety tests indicates alcohol or drug impairment. 

However, these “standardized” field sobriety tests are not perfect. Even if the conditions are ideal and the police officer administers the FSTs precisely as directed by the NHTSA guidelines, the results of field sobriety tests can be inaccurate. According to the Instructor Guide provided by the National Highway Traffic Safety Administration, the accuracy levels for the FSTs are:

• Walk and Turn Test – 79% accurate
• One Leg Stand Test – 83% accurate
• Horizontal Gaze Nystagmus Test – 88% accurate

California drivers need to understand their rights regarding field sobriety tests. For example, a California driver does not have to take the field sobriety tests when stopped for suspicion of drunk driving.

California Drivers Can Refuse to Take Field Sobriety Tests

If you are pulled over for drunk driving, the police officer will ask you to take the field sobriety tests. He is looking for signs of impairment based on your performance on the FSTs. California does not impose any penalty for refusing to take field sobriety tests during a traffic stop.

As experienced DUI defense lawyers, we generally recommend that California drivers respectfully decline to take field sobriety tests for several reasons. Primarily, a sober person can fail a field sobriety test for reasons that have nothing to do with alcohol or drugs in their system. 

Unlike chemical tests (i.e., urine, blood, or breath test) that determine your blood alcohol content (BAC), the field sobriety test the officer gives you is a subjective review of “signs” that could indicate you are a drunk driver. The officer may have already made up his mind about arresting you for drunk driving. Taking the FSTs gives the police officer additional “evidence” to present to the court that justifies the DUI charges.

Failing field sobriety tests could result in one or more charges under the California Vehicle Code, including driving under the influence and DUID (driving under the influence of drugs).

To help you understand how California field sobriety tests work and how the results can be incorrect, we discuss the standardized FSTs and some non-standard field sobriety tests used by California police officers during a DUI stop.

DUI Field Sobriety Tests Used in California

As discussed above, the NHTSA has approved three field sobriety tests to be used by police officers during a roadside DUI investigation. The NHTSA considers these tests to be good indicators of a person’s impairment. 

The NHTSA bases its “validation” of these tests in part on a study by the Sand Diego Police Department. The study reported a strong connection between poor performance on these tests and alcohol or drug impairment. The tests are collectively referred to as the “standardized FSTs.” 

The Walk and Turn Test (WAT Test)

This divided attention test requires a person to simultaneously concentrate on a physical and mental task. For the test to be accurate, the police officer must give the person exact instructions for completing the test. The person must remember the instructions and complete them in order correctly.

Generally, the police officer tells the person to take nine heel-to-toe steps in a straight line (either a line on the road or an imaginary line). After completing nine heel-to-toe steps, turn around and take nine heel-to-toe steps back to the beginning point.

There are eight signs that the police officer may notate that could indicate the person is intoxicated or under the influence of drugs:

• Starts walking too soon
• Cannot maintain balance during the instructions
• Fails to walk in a heel to toe fashion
• Uses the arms to balance 
• Takes the wrong number of steps
• Stops while walking
• Steps off the line
• Fails to make the turn correctly

This FST has a 79% accuracy rating for indicating a BAC of .08 or greater because of poor performance. There could be many reasons why a person is unable to maintain balance while walking heel to toe.

The Horizontal Gaze Nystagmus Test (HGN Test)

Nystagmus is the involuntary movement or “jerking” of the eyes from side to side, up and down, or in a circle. Horizontal nystagmus describes the uncontrollable and rapid movement of the eyes from side to side. 

The HGN test given during a roadside field sobriety test involves the police officer noting the angel of the eye when it begins to “jerk” (exhibit nystagmus) as it moves side to side. The officer performs the test by moving a stimulus, such as a pen, from left to right and instructing the person to follow the object with their eyes.

Nystagmus at or before the 45-degree angle of the eye movement is associated with a high level of alcohol in the person’s system. However, the accuracy level of the HGN test is roughly 88%, according to the NHTSA. Therefore, the results of this field sobriety tests could be incorrect in at least 12% of the cases.

The One Leg Stand Test (OST Test)

This field sobriety test is another divided attention test used during a DUI traffic stop. While this test has a better accuracy rating according to the NHTSA, it still leaves a lot of room for errors.

During the OLT test, the police officer instructs the person to lift their foot about six inches off the ground. While holding that position, count from 1001 to 1030 and then look down at their foot.

Signs of impairment that the officer looks for during the test include swaying, hopping, using the arms to balance, and putting the foot down before completing the test.

Non-Standard DUI Field Sobriety Tests Used by Police Offices

In addition to the “standardized” field sobriety tests, police officers use various non-standard field sobriety tests during a DUI stop. The NHTSA has not approved or validated these tests because there is little to no evidence that poor performance on these tests indicates DUI impairment. Furthermore, the way the tests are administered can vary significantly from one law enforcement officer to another, increasing the chance that the test results are inaccurate. 

Several “signs” the officer looks for when performing these non-standard FSTs include:

• Ability to follow instructions, including counting correctly, starting and stopping correctly, and remembering instructions 
• Ability to balance and stand still
• Muscle tone and body/eye tremors
• Depth perception 
• Uttering unusual phrases or sounds
• Lack of muscle control
• Ability to perform mental and physical tasks simultaneously 

Some of the non-standard field sobriety tests used by California police officers include:

Finger Count Test

The police officer instructs the person to extend their hand with the palm facing upward in front of their body. Then, touch the top of the thumb to each finger, beginning with the index finger and working their way over to the little finger. While touching each finger, the person should count from one to four aloud. Then, the process is reversed for a total of three sets. 

Finger to Nose Test

This non-standard FST is one of the most common field sobriety tests officers perform. First, a police officer instructs the person to stand with their feet together and their arms at their sides. Then, after making a fist with each hand and keeping the index finger extended, the person must tilt their head back and close their eyes. 

The officer then instructs the person to extend either the left or right arm in front of their body and use their index finger to touch their nose. If the person cannot perform the test correctly, it is thought to be a sign of intoxication because the person lacks muscle control and coordination.

Romberg Balance Test

A police officer instructs the person to stand with their feet together, and their head tilted slightly backward. Then, with their eyes closed, the person must estimate when 30 seconds have passed. Finally, when they believe 30 seconds have passed, they will tilt their head forward, open their eyes, and say stop.

Hand Pat Test

The officer instructs the person to extend either the left or right hand in front of their body with the palm facing upward. Then, place their other hand on the top of that hand with the palm facing down. 

Keeping the bottom hand in the same location, the person must use the top hand to “pat” the bottom hand while counting “one, two, one, two, etc.” In addition, the person must rotate their top hand on each of the counts so that they pat their bottom hand palm down on the “one” counts and palm up on the “two” counts.

What Can Affect the Accuracy of a DUI Field Sobriety Test?

Many things can affect the accuracy of DUI field sobriety tests. For example, there are several medical reasons why a person would exhibit signs of nystagmus, including multiple sclerosis, head injuries, certain medications, and cataracts. 

Numerous physical and mental conditions may affect the accuracy of a test. Age, weight, inner ear problems, mental disabilities, anxiety, physical pain, and illness are just a few examples of why a person could “fail” a field sobriety test when they are not impaired by alcohol or drugs. In addition, being tired, having muscle fatigue from work or exercise, and stress can negatively impact a person’s ability to perform field sobriety tests correctly.

Weather and field conditions can have a significant impact on FST results. For example, if the test is given on an uneven surface, it increases the chance the person will lose their balance. In addition, bright lights from oncoming traffic and noise can affect test results.

The police officer’s conduct can result in inaccurate test results. For example, if the police officer does not provide clear instructions, the person may “fail” the test. Likewise, if the officer moves around, it can distract the person and result in inaccurate test results.

Even something as simple as wearing high heels, tight clothing, or baggy pants could adversely affect a person’s performance on field sobriety tests.

Fighting the Results of DUI Field Sobriety Tests in California

If you are arrested for DUI in California, you should discuss your legal options with a DUI defense attorney before pleading guilty to driving under the influence. There may be one or more grounds for challenging field sobriety tests.