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Challenging The Blood Test In A California Dui Case


Challenging the Blood Test in a California DUI Case

If you’ve been charged with a DUI in California, one of the first things you may be wondering is how strong the evidence against you is. In particular, you’ll likely be curious about the blood test results. What if there’s something wrong with those results? Can they be challenged in court?

In this post, we’ll explore some of the ways that you can challenge blood test evidence in a California DUI case and how a California DUI attorney can help you in challenging the blood test in a DUI case.

Keep reading to learn more.

How Accurate Are BAC Blood Tests?

Blood alcohol concentration (“BAC”) blood tests can be very accurate, but sometimes they produce misleading results. The absolute percentage might be “correct,” but offer an incomplete or inaccurate picture of the person’s blood alcohol concentration.

If the sample got contaminated in one of several ways, the testing procedure might be reading the alteration rather than the individual’s actual BAC. For example, if the person drawing the blood cleans the surface of the skin with an alcohol swab before inserting the needle into the vein, the blood sample can get contaminated with the alcohol from the swab.

The blood sample should be collected by a trained professional who follows protocols to the letter. Another issue is the environment where the blood draw occurred. The sample should be drawn when the defendant is in a proper medical environment.

Also, blood alcohol levels change over time. If there is a delay in having the blood sample collected, the test results might not be accurately reflective of the person’s BAC at the time of the traffic stop.

How Long Does It Take to Get a Blood Test Back for Alcohol?

Unlike courtroom drama television shows, in real life, a quick turnaround for a BAC blood test is when you can receive a result in a month to a month and a half. Often, results take significantly longer.

For example, in a large city where a laboratory is trying to process many BAC tests, the wait for test results could require much greater patience. Also, if your lawyer files a motion for blood split testing, the timeframe will depend on the independent laboratory’s workload and efficiency.

What Can Affect a Blood Alcohol Test?

Age, gender, weight, and several other factors can affect the results of your blood alcohol test. In general, the older you get, the faster your BAC goes up after a drink. The BAC in women usually rises faster than in men. The BAC will go up more quickly in people who weigh less than in people who weigh more.

Certain medications can heighten the effect of alcohol, raising a person’s BAC faster than they might expect. Some illegal drugs can have a similar effect.

Some racial or ethnic groups will generally process alcohol slower than others, which can result in a higher BAC and in less time.

When you drink on an empty stomach, your BAC goes up more quickly than if you ate something before or during your consumption of alcoholic beverages.

Also, different kinds of drinks can affect you differently in terms of your BAC. A glass of wine, a bottle of beer, and a cocktail can have vastly different amounts of alcohol. Even within the same category, there can be marked differences in the strength of the alcohol. One kind of cocktail, for example, a Long Island Iced Tea, can contain far more alcohol than another, like a Campari and soda.

Does a Breathalyzer Read Higher than a Blood Test?

Some factors can cause a Breathalyzer result to spike more quickly than a blood test, while some other factors could cause a blood test to show a higher BAC sooner than a breath test. For example, if a person has mouth alcohol, a breathalyzer will show a higher rating than a blood test.

Usually, however, a breathalyzer does not read higher than a blood test because of the biological process of how the body metabolizes alcohol. When you consume an alcoholic beverage, the alcohol goes into the mouth, down the throat, and into the stomach.

As part of the digestion process, the stomach will absorb some of the alcohol, which will then pass into the bloodstream. If you had something to eat before or while you drink, some of the alcohol will not be in direct contact with small intestines, so the absorption of alcohol into the bloodstream will be slower.

On the other hand, if you do not have food in your stomach when you drink alcohol, your digestive tract will absorb alcohol and release it into the bloodstream. The absorbed alcohol gets into your lungs as blood passes through the vessels in your lungs. Only then can a breathalyzer measure your BAC, as long as you do not have mouth alcohol.

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

If you think that someone made an error in your blood test, there are several ways to challenge that fact in court. Some challenges are based on BAC results that are unreliable. For example, the lab might have inadvertently switched samples. Also, samples can get intermingled with other samples if there is not enough blood to run a test.

The blood sample could get contaminated after collection, leading to an inaccurate result. The use of improper collection procedures, like wiping the surface of the skin with an alcohol swab, could result in a false positive result. Sometimes, the blood sample ferments inside the tube. The fermentation process can cause the sample itself to make alcohol.

Violation of Title 17 regulations can be grounds for challenging the results of DUI blood testing. If the equipment has not been maintained properly and calibrated as required, there is no way to know if the readings are accurate.

If your complaint about the test results centers on the lab equipment or the quality of the testing procedures rather than about the blood sample itself, your attorney could request a blood split order. If granted, the judge will order the lab to separate some of the blood sample so that you can have it sent to an independent lab for verification of the BAC results.

Can You Challenge a DUI Blood Test?

Yes, you most certainly can challenge a DUI blood test if you have grounds for doing so. Of course, the first step in this process is assessing whether the BAC results the prosecutor is relying upon sound feasible. Having a level of 0.08 or higher could be expected if you weigh 110 pounds and had six double vodkas at a bar in one hour right before getting behind the wheel. On the other hand, if a professional linebacker had one beer with a double cheeseburger and fries three hours before getting pulled over, a level of 0.08 or higher would make no sense at all.

Sometimes, people have no idea what mistake caused the incorrect DUI blood test results, but they know that they were neither drunk nor impaired. If that is your situation, a California DUI attorney can help you try to discover what went wrong. When the investigation uncovers the error, the blood test can be challenged, and the court can be asked to remove it from the evidence the prosecutor can use against you.

Even if there is not an error in the blood draw, the sample, or the performance of the laboratory test, you might still have an argument. An example of this would be if the officer pulled you over illegally. Thus, any charges against you should get dismissed.

How Law Enforcement Uses Blood Tests to Measure Blood Alcohol Concentration (“BAC”) in Drunk Driving Investigations and How the Defense Can Challenge the Results in Court

California has implied consent laws, which give police the authority to ask people to submit to a blood test after arresting them for a DUI. The police take the suspect to an appropriate facility to have a trained professional draw the blood. The blood tube gets labeled with the identification of the suspect. The sample gets sent to a laboratory.

After at least a few weeks, the results come back from the lab, establishing what should be precise measurements of the alcohol in the person’s bloodstream and whether any drugs were present. The prosecutor analyzes the test results to determine whether there is a criminal case against the defendant. If the BAC exceeded the legal limit, or legal or illegal drugs or other substances were found that could impair a person’s ability to drive safely, the prosecutor will decide whether to file charges.

However, all is not lost just because the prosecutor files criminal charges. The defense can challenge the results in court if any errors were made at any point in the testing process. The available challenge will depend on the unique facts of each case. For example, if the laboratory did not follow protocol in the storage of the blood sample vial, fermentation could happen. There is no way to separate how much of the alcohol that later gets measured is because of the fermentation and how much was from the defendant’s consumption of alcoholic drinks.

Blood Testing Procedures

MEDLINE Plus, a division of the National Institutes of Health, describes how a healthcare professional draws blood from a suspect’s arm. The medical professional will clean the surface of the arm and insert a small needle into the defendant’s arm. The needle is attached to a glass tube, where the blood gets collected. As soon as there is a sufficient quantity of blood in the tube, the healthcare personnel will remove the needle from the individual’s arm, stop the bleeding with a cotton ball, and apply an adhesive bandage or a piece of paper tape.

The Cleveland Clinic explains that the amount of alcohol in a person’s blood, also called “blood alcohol concentration” or “BAC,” is the amount of alcohol that the stomach and small intestines have absorbed after a person drinks alcohol, and that their liver has not yet filtered out through metabolizing the alcohol. 

Some people develop a high tolerance to alcohol over time. It takes a larger quantity of alcohol for them to feel the effects of the substance. Still, a person with a high alcohol tolerance can have a surprisingly high BAC, even though they do not even feel buzzed. A person’s BAC measures the volume of alcohol in the blood. A BAC is not a measure of the feeling of drunkenness, also called intoxication.

Challenging Blood Test Results in Court

It is possible to successfully challenge blood test results in court. However, fighting DUI charges is not a job for amateurs. Lawyers who represent people charged with drunk driving, however, know multiple ways to attack the use of blood test results in their clients’ DUI cases.

If a police officer violates a driver’s constitutional rights, that, in and of itself, can be grounds to challenge blood test results that came out of an improper traffic stop. Chain of custody issues can also be a powerful defense because they can cast doubt on whether the blood sample that got tested was actually that of the defendant.

Getting Help from a DUI Attorney

You do not have to go through this stressful situation by yourself. A good California DUI lawyer can talk to you and help develop a strategy for your defense. Whether you had blood alcohol testing, breath testing, or both, you will want to work with a California DUI attorney to try to achieve the best possible outcome in your circumstances.

How Accurate is a Blood Test for DUI? How Do I Challenge a DUI Blood Test and Dispute the Results?

A blood test is only one of many methods that law enforcement officers use to try to determine whether a person can be charged with drunk driving. The police can also use blood tests, breath analysis, physical observations, field sobriety testing, and urine tests in their investigations.

Blood testing is expensive compared to other forms of DUI chemical testing. Also, blood testing is inconvenient, uncomfortable, and invasive. The other forms of BAC analysis do not involve jabbing a needle into a suspect’s arm.

Assuming that the blood sample was drawn correctly and handled properly, and that the testing procedures were performed using scientific protocols, the testing results can be highly accurate. Of course, other factors that can affect the accuracy of the result, including a delay in drawing the blood sample, a delay in running the test on a blood sample such that fermentation can result, losing a blood sample, mixing up a suspect’s blood sample with someone else’s, and contaminating the defendant’s blood sample with a foreign substance.

Complications Surrounding Blood Testing for DUI and the Prosecution

Not everyone is a good candidate for a DUI blood test. For people with certain health conditions, it can be dangerous to subject them to having their blood drawn. For example, people who take anticoagulant medication should not be forced to have a blood BAC test. Instead, they should be offered a breathalyzer test or urine test.

Other medical conditions that can have a health exemption for chemical testing by blood sample include certain heart conditions and hemophilia. If the suspect notifies the police of the condition, the officer breaks the law if they force the individual to undergo a blood draw.

What Can I Do for Legal Methods to Fight a DUI Blood Test Level Case?

When your lawyer uncovers evidence of an error made in your DUI blood test, they can file a motion before trial, asking the judge to suppress or exclude the evidence. If the judge agrees that the test results should not come in at the trial to get used against you, the jury will not see that evidence.

Blood test results are crucial evidence in a drunk driving case. If the prosecution relied on the blood tests for establishing the defendant’s BAC and the judge throws out that evidence, the judge might dismiss the case. Mounting a successful challenge to blood test results is a way to create reasonable doubt as to the defendant’s guilt.

The Importance of Analyzing Different Blood Alcohol Content Levels

The National Institutes of Health has published studies that show the variability of blood alcohol concentration (“BAC”) assessments. These studies establish that forensic alcohol analysis involves measurement uncertainty. Because of the variability of results, and the criminal consequences that can happen when courts rely on these BAC measurements, some researchers recommend multiple assessments to reduce errors caused by measurement uncertainty.

What is Reasonable Cause Under the Law for Having to Take the DUI or DWI Blood Test?

Reasonable cause has to do with an officer’s belief that the driver was operating a motor vehicle while under the influence of alcohol, a drug, or both. Reasonable cause is a much lower standard of proof than the well-known standard of “beyond a reasonable doubt.” For the beyond a reasonable doubt standard of proof, a  jury must find, beyond a reasonable doubt, that the defendant committed the act with which they were charged before they can issue a guilty verdict.

Reasonable cause, however, can be that the officer observed behavior consistent with the driver being under the influence of alcohol or drugs. For example, finding a driver who is slumped over the wheel in a traffic lane could indicate that the individual lost consciousness due to intoxication. On the other hand, the situation could be the result of a medical emergency.

When Is a DUI Blood Test Required by California Law?

When a California police officer believes that a driver who is under the influence of alcohol or drugs caused an accident, they can request a warrant that could force the driver to have a BAC blood test. Law enforcement can also require a blood test when a driver is deceased or is not conscious.

When a suspected drunk driver cannot take a breath test because of a medical condition like chronic obstructive pulmonary disease (COPD), the officer could require a blood or urine test. If the police suspect the driver of driving under the influence of drugs, a breath test for alcohol will be useless. A blood test is necessary to find the presence of drugs in a person’s bloodstream.

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

For people who pass out at the sight of a needle, the thought of having a blood draw for a BAC is terrifying. A person in that situation will likely opt for a breath test or a urine test. People who cannot blow hard enough to get a testable sample of breath might find a blood test or breath analysis to be their only option.

People who have mouth alcohol because of recent use of breath fresheners might find it better to give a urine or blood sample. If you are on a high protein, low carbohydrate diet or you have a medical condition that causes your body to generate a high quantity of ketones, a breath analysis might cause a false positive result.

What Are the Title 17 Regulations?

The California legislature recognized that peoples’ lives could get ruined by errors in DUI breath tests, blood tests, and urine tests. To protect Californians from this unfair consequence, Title 17 of the California Code of Regulations created rules that govern how law enforcement can conduct these tests.

Are Blood Test Results Presumed to Be Valid?

Although there is generally a presumption that blood test results are valid, your defense counsel can submit evidence that might rebut the presumption.

Can the Police Force a Person to Take a Blood Test?

Yes, if a judge issues a warrant for the forcible drawing of a blood sample, the police can obtain the blood draw against the will of the subject individual. The police are allowed to use as many officers as needed to hold down the person while their blood gets drawn.

Can a Driver Have Blood Tested in an Independent Laboratory?

Yes, a driver can have their blood tested in an independent laboratory. The defense lawyer will file a motion requesting a blood split. If granted, the sample of the defendant’s previously-drawn blood will get divided into two parts, thus enabling testing in a different laboratory.

Challenging Blood Tests in DUIs Involving Drugs

Many of the same challenges that are available for BAC blood test results are also available in DUI or DUI-D cases involving drugs. The police must follow the Title 17 regulations to the letter, and draw, store, and test the blood sample according to protocol. If there were errors made, the defense can challenge the use of the blood test results.

Get an Experienced DUI Attorney on Your Side

You don’t have to do this alone. In fact, representing yourself is ill-advised. Talk to one of our highly qualified California DUI attorneys for help on challenging BAC blood test results by reaching out to us here.


The post Challenging the Blood Test in a California DUI Case appeared first on Law Offices of Taylor and Taylor - DUI Central.

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