Blood alcohol content/concentration (BAC) refers to a measure or expression of the level or content of alcohol in an individual's blood. Usually, the law expresses BAC in percentage. In the state of California, the legal BAC limit for adult drivers is .08%. Blood alcohol content expresses the grams or content of alcohol found in every hundred milliliters of a person's blood.  If you have a low BAC, it is an indication that you have a lower concentration of blood in your system. If you have a higher percentage of BAC, it is an indication that you are intoxicated, and you may face charges for driving with a BAC of 0.08% or more, or DUI charges. We at the Orange County DUI Defense Attorney Law Firm can help you fight charges of driving with a BAC of more than .08%.

Measurement of Blood Alcohol Content

Several methods of measuring BAC exist in California. The most commonly used methods of measuring BAC include a Blood test or through a Breath test. The law considers Chemical tests to be scientifically accurate and reliable in measuring the amount of alcohol in the blood. According to California law, Chemical tests are applicable as reliable evidence in the prosecution of DUI cases.

Breath Tests

Most officers use Breath tests to measure blood alcohol content. The main reason for the popularity of breath tests is that they are less invasive than blood tests. Breath tests are also reliable, and they offer instant results. There are two main categories of breath tests in California: the pre-arrest breath test and the post-arrest test of your breath. The pre-arrest breath test also goes by the name (PAS) (preliminary alcohol -screening) test. 

Most people may not understand Breath tests and how they establish the BAC level or the level of intoxication. Unlike blood tests, breath tests do not measure the amount or the level of alcohol available in your blood directly. Instead, a breath test determines the alcohol level in the deepest/interior part of your lungs. The deepest part of your lung is close to your blood supply. The law officers use special measuring equipment known as a breathalyzer. The breathalyzer measures/weighs the alcohol content deep in your lungs and then converts the results in a percentage.  The breathalyzer uses the partition ratio to express the results into a percentage. In California, the partition ratio is 2100 to 1. The ration may differ from situation to situation or from individual to individual. However, the state of California adopts a single partition ratio. If you interpret the 2100 to 1 ratio, it implies that the level of alcohol present in a person's 2,100 ml (milliliters) of inner lung breath is similar to the blood level available in the person's 1 ml of blood. 

The PAS Test

The police administer the PAS test before they arrest you for DUI.  When the police stop your car on suspicion that you are under the influence, the officers may administer the PAS test. The officers may also administer the PAS test at a DUI checkpoint.  A driver has a legal right to decline a PAS test without facing any consequences. However, in some instances, the driver must submit to a PAS test. A driver must submit to a PAS test if the driver is less than 21 years old. If you are serving probation after committing a previous DUI offense, you have to submit to a PAS test. However, if you are not under probation, and if you are above the age of 21 years, you are under no obligation to submit to a PAS test. 

Post-Arrest Breath Tests

When the police legally arrest you for DUI in California, the police allow you to choose between a Breath test or a Blood test. The law requires you to submit to a post-arrest test of your breath. You have to submit to the test/measurement even if you had previously undergone a PAS test.  You may face detrimental consequences if you refuse to submit to a post-arrest test of your breath to test for intoxication. Some of the penalties for refusing to submit to a DUI test include suspension of your driver's license for a minimum period of one year. 

When given the opportunity to choose between a blood test and a breath test, most people opt to undergo a breath test.  This is because the Breath test is mild or less- invasive. The police mainly administer the post-arrest test of your breath at the police station on a desktop device. The administration of the post-arrest test of your breath is in many ways similar to the administration of a PAS breath test.  In some instances, the officers may administer the post-arrest test of your breath by the roadside. If the police administer the test by the roadside, the test may be similar to the PAS test. However, there is one major difference; a post-arrest test is mandatory even if the police administer it at the roadside. 

Measuring BAC using Blood Tests

The officers may measure the level of alcohol in your blood directly using the blood tests.  A blood test is the most reliable test for measuring blood alcohol concentration in a person's blood.  However, for the results of the blood test to be reliable, the testing officer has to do everything under the right procedure.  It is only a person with a license from the state who should draw a driver's blood sample.  Upon drawing a sample of the blood, the officer sends the sample to a laboratory for analysis. You may have to wait for several weeks before you or your lawyer can get the results of a blood test. 

A blood test offers an advantage over the breath test because it is easy to save a sample of the defendant's blood. Therefore, the law can also get his/her independent expert to test the sample of the defendant's blood. The attorney can then compare the results availed by the independent expert with the results offered by the officer. To be able to test the defendant's blood independently, your attorney would have to apply for a "blood-split motion." This motion allows the attorney to get part of the blood sample obtained by the police and send the blood to a laboratory of the attorney's choice for analysis.  If the results from the independent lab differ from the results provided by the prosecutor, the attorney may challenge the credibility of the prosecutor's Blood test results. 

Measuring BAC Using Urine

In California DUI cases, the officers may measure your blood alcohol content using your urine.  Urine tests are effective and accurate in measuring the level of alcohol in a person's blood.  However, in establishing the specific level of alcohol in your blood, urine tests are not as effective as blood tests or breath tests.  Therefore, most officers will not conduct a urine test to measure BAC.

However, a urine test may come in handy in measuring the blood alcohol content in some instances. If both the breath and the blood tests are unavailable, an officer may have no option but to use a urine test. If, after an arrest, you are unable to take one test, and the other test is not available, the officer may conduct a urine test.  A person may not have the ability to take a blood test or a breath test if he/she has a medical/health condition like a blood disorder or a breathing problem. A person may also not be able to undergo breath testing due to a high level of unconsciousness or inebriation. 

The Allowable BAC Level in California

According to California law, a person who operates a vehicle with a particular level of alcohol in the blood is under the influence.  This is under the "per se" DUI laws in California. "Per se" means "in itself." This means that according to the law, you are under the influence, and you have violated the law as long as your BAC is above the legal limit. As long as your blood alcohol content exceeds the set legal limit, no other proof is necessary to show that you are intoxicated.  The prosecutor is under no obligation to show that you were impaired as long as your BAC is above the legal limit. 

The legal BAC levels in California vary depending on several factors. For adults and non-commercial drivers, the legal BAC is .08%. If a driver in this category operates a vehicle with a BAC that exceeds this limit, he/she violates the California VC 21352 (b). For drivers under the age of 21 years, the allowable BAC is .05%. If a driver below the age of 21 years operates a vehicle with a BAC that is above .05%, the driver violates the California VC 23140. If you are a driver of a commercial vehicle, your allowable blood alcohol content is .04%. If you operate a vehicle with a blood alcohol content that exceeds this level, you are violating the California VC 23152 (d). If you are a taxi or Uber driver commonly known as "passengers for hire," the allowable legal BAC limit is .04%, just like for commercial vehicle drivers. If you operate a taxi with a BAC that exceeds .04%, you will be violating the California VC 23152 (e). 

If you are an underage driver, you may be subject to California's zero-tolerance law. This law states that you should not have even the slightest amount of alcohol in your blood. According to California law, it is illegal for an underage driver to be in possession of alcohol. Two statutes outline the zero-tolerance law: California VC 23136 and the California VC 23154. If you are below the age of 21 years or if you are on probation, you may violate the zero-tolerance law if your BAC exceeds the zero-tolerance limits. 

Choosing Between a Blood Test and a Breath Test

Upon an arrest for DUI in California, you may be confused about the DUI testing method to choose from. The police allow you to choose between a breath test and a blood test. Many people may refuse to submit to a breath test and later submit to a blood test.  There is no clear line on the best BAC measuring method. Both the breath test and the blood test have a set of advantages and disadvantages. It is important to understand the advantages and disadvantages of both methods to be able to make the best choice.  You should also relax by knowing that an attorney can challenge both the results of a breath test or a blood test in court.  Whether you opt for a breath test or a blood test, it is advisable to be polite during the testing. It is also advisable to say as little as possible during the test. In addition to using the results of the DUI chemical test to convict you of driving under the influence, the officer may also testify about what you said during the arrest and the testing process. 

Most people choose to undergo a breath test upon an arrest for DUI in California. This is because the method is less invasive and is, therefore, less stressful for most people. The results from a breath test are also available immediately. You will not have to wait for weeks before you can be able to access the results. 

On the other hand, a blood test also has some advantages, despite being more invasive than a breath test. Your blood sample will allow for a more accurate assessment of your blood alcohol content than the analysis of your deep lung breath.  If you are very close to the legal limit, but you have not exceeded the legal limit, a blood test will give a clear picture of your blood level.  A blood test also gives you the option of having a sample of your blood saved. Your attorney may then independently request an expert to test your blood sample to show if indeed you were under the influence. In the case of a breath test, it is not possible to preserve a breath sample. 

Importance of BAC During Prosecution

When presenting a DUI case against you, the prosecutor uses your BAC results alongside other evidence he/she may have against you.  The prosecutor strives to show that your BAC was above the allowable limit, and you are therefore guilty of DUI according to "Per se" DUI laws.  The prosecutor may also seek to show that you were impaired at the time of the DUI offense. In California, DUI is a subjective test. The prosecutor has to show that you were unable to operate a vehicle well due to intoxication with alcohol. 

BAC is one of the elements of subjective driving under the influence of prosecution.  If you record a high level of BAC, it is an indication that you were impaired. However, even with your BAC results being over the legal limit, the court may require additional evidence to prove impairment. Additional evidence that the court may use include the testimony of the officer. The officer may state in court that our driving type and your physical behavior were signs of intoxication. The prosecutor may also present in court proof of when you drove. This is to indicate that at the time of the arrest, you were driving a vehicle while impaired.  The court may rely on witnesses like passengers in the car you were driving at the time of the DUI arrest.   

Fighting BAC Test Results

Just because an officer measured your BAC and obtained certain results does not mean that the results are true.   You may challenge your BAC results in court with the help of an attorney. According to Title 17 of the California Code of Regulations, strict procedures for Chemical tests exist.  If the testing officer fails to follow the procedures to the letter, an experienced DUI attorney can challenge the credibility of the results.  Various ways of challenging BAC results include: 

Errors in Blood Testing

Blood tests are prone to several errors, and if you suspect that there is an error in your BAC results, you may challenge the testing procedure.  Title 17 of the code of regulations outlines the rules that the testing officer has to follow. If the testing officer violates the rules, the results of a blood test may be invalid. Some of the mistakes an officer may make while conducting a blood test and which may affect the credibility of the results include contaminating the blood sample collected.

 Upon drawing a blood sample from the driver, the officers have to handle the sample properly to avoid contamination. BAC results may be unreliable in case of switching or intermingling of the blood samples. The fermentation of the blood sample may occur mainly due to poor storage. If fermentation takes place, the sample may produce alcohol characteristics.

Errors in Conducting a Breath Test

Just like blood tests, Breath tests are also prone to several errors, and the errors may affect the credibility of the results.  If errors occur, the results of a breath test may not accurately reflect your BAC, and you would have a good ground to challenge the results in court.  An error may occur if the testing officer fails to follow the right breath testing procedures. You may challenge the results of the breath testing device was not in good working condition at the time of the testing. The law requires a calibration of the breathalyzer every ten days after every 150 uses, whichever happens first.  The person conducting the breath test must have the right qualifications on how to use the device.  

Before administering the breath test, the testing officer should observe the defendant for a minimum of fifteen minutes. During this observation period, the officer should not allow the defendant to smoke, to eat, drink, or put something in the mouth. The defendant should also not vomit, regurgitate, or burp before the testing procedure. Burping or regurgitating may bring alcohol from the stomach to the mouth, and this may lead to unreliably high BAC results. 

When conducting the Breath test, the officer should collect air from deep within the lungs. The law requires the testing officer to obtain two breath samples, and the samples should not differ from each other with more than 0.02 grams per 100 milliliters of blood. If you feel that the testing officer did not follow the right procedure, you may challenge the BAC measurements in court. 

A Low Carb Diet Influenced the BAC Results

It is common for some diets or some medical conditions to make your body produce substances that are chemically similar to alcohol.  The chemical substances with similar characteristics to alcohol are known as ketones.  Ketones may influence your BAC results because the breath testing equipment may not always be able to distinguish between alcohol and ketones. Also, the presence of ketones may lead to a smell that is similar to that of alcohol.  Therefore, the breath testing equipment may record elevated BAC results, yet you are not impaired. 

Some medical conditions may make the body produce ketones. Some of the medical conditions that may lead to the production of ketones include diabetes. The body may also produce ketones due to Hypoglycemia. If you are fasting, and if you are on a high-protein and low-carbohydrate diet, you may record higher BAC results than normal. 

High BAC Results Due to Mouth Alcohol

After you consume alcohol, some traces of the alcohol may remain in the linings of your mouth.  This leads to residual mouth alcohol, which may lead to elevated BAC results.  The Breath test detects the residual mouth alcohol even if the alcohol is not yet absorbed in your bloodstream.  You may challenge the BAC results if you suspect that the high results were due to mouth alcohol. 

Contact an Orange County DUI Defense Attorney near Me

If your BAC exceeds the allowable limit of .08%, you will be guilty or liable of driving under the influence, according to California law. The consequences for this offense may include serving jail time, probation, fines, or suspension of your driver's license. You may also face other charges for underage DUI or commercial DUI, depending on your BAC. You can contact the Orange County DUI Defense Attorney Law Firm at 714-740-7866 and speak to one of our attorneys if you are facing DUI charges.