DUI testing is crucial for cracking down on drunk drivers and helping to make the roads safer for all, but there are a lot of myths and misconceptions about how DUI testing actually works, with some people suggesting that there are ways to cheat the test, for example.
In this guide, we’ll bust some of the most common DUI testing myths, explaining how testing really works and covering the key pieces of information you need to know if you’re ever pulled over and tested.
Types of DUI Tests
Before we get to the myths regarding DUI testing, it’s important to have a clear understanding of some of the different varieties of tests that the police may use to determine whether or not a driver is under the influence of drugs or alcohol.
Blood Tests
Blood tests are regarded by many experts as the most accurate type of DUI testing to determine a person’s blood-alcohol content (BAC). Drivers have to provide consent to have a blood test carried out, but refusing to give consent can result in the suspension of your license.
Breath Tests
Breath tests are the most common method used by police officers to check a person’s BAC. Typically, they involve the use of a breathalyzer device, which analyzes the contents of a person’s breath and can detect traces of alcohol in the breath.
Urine Tests
Finally, there are urine tests, which are considered the least accurate of the three and are only really used as a ‘last resort’. Urine testing can’t usually be performed right at the time of the stop, so it can be difficult to get a precise reading with this method.
Myths and Misconceptions Surrounding DUI Testing
Next, let’s look at some of the many myths and misconceptions around DUI testing, explaining why those myths are false.
Your Blood Alcohol Content Needs to Be 0.08 Percent or Higher to Get a DUI
This is a common myth that has spread across the US, but if you think that your BAC needs to be at least 0.08% to be charged with a DUI, this information is false. In reality, the chargeable BAC level varies from state to state, and officers can often arrest you if they feel that your abilities are impaired, no matter what your BAC happens to be.
If I Pass the Field Sobriety Test, I Can’t Be Charged with a DUI
Even if you pass the field sobriety test, there’s still a chance that the officer may arrest you. They may have other reasons to believe that you were driving under the influence, so passing the field tests is not at all a guarantee that you won’t be arrested.
DUI Testing Is Just a Way for the Police to Make Money
This is also not true. DUI testing is carried out for public safety, in order to reduce the number of drunk or drug-using drivers on the roads and minimize the chances of people being involved in dangerous or deadly accidents.
Law Enforcers Have to Catch You Driving to Arrest You for DUI
This one might sound logical, but it’s not true. While most DUI arrests involve officers catching and stopping people driving, law enforcement personnel can also arrest you and test you for a DUI if they see you parked and getting out of a vehicle.
You Can Trick the Breathalyzer by Sucking a Penny
This is a myth that has spread all over the world for many years, but there’s actually no truth to it. With modern breathalyzer devices, sucking a penny (or any other coin) has absolutely no impact on the results.
It’s Just a DUI Charge. I Don’t Need a Lawyer.
This is a common mistake that a lot of people make, and it can cause them to end up in far more trouble than they initially expected. Having a DUI defense lawyer on your side can make a huge difference in DUI cases and can help you avoid punishment or obtain a lesser punishment.
Accuracy of DUI Tests
The accuracy of DUI tests is often called into question, and it can be a key factor used by defense lawyers to help their clients avoid punishment. Even though these testing methods have a good degree of accuracy in general, their reliability levels can vary, and various factors may produce unreliable results.
Factors That Can Affect the Accuracy of the Test Results
There are multiple factors that can influence the results of DUI testing. For example, breathalyzer devices are not programmed to differentiate between the people taking them; they essentially operate on the assumption that every test subject is the same, and this can lead to inaccurate results, as a person’s job, lifestyle, or diet may impact their breath test results.
Medical conditions and medications may also affect DUI test results and even residual alcohol in the mouth from products like mouthwash or breath freshening sprays may be detected on a breathalyzer. Environmental factors, like the presence of paint or acetone, can also skew the results.
In addition. cannabis is a factor that can affect the accuracy of DUI test results as well. Cannabis use can impair a person’s ability to drive safely and can also impact their performance on field sobriety tests. The primary psychoactive compound in cannabis, THC, can remain in a person’s system for several hours or even days and weeks after use. This means that a person who has used cannabis may still test positive for THC in a DUI test, even if they are no longer impaired.
False positives and false negatives can occur in DUI tests, which can result in wrongful arrests or charges being dropped against impaired drivers. It is essential to ensure that DUI tests are administered accurately and reliably to prevent these errors.
How False Positives and False Negatives Can Occur
Even though testing devices and processes have a good degree of accuracy, they’re not flawless. False positives and false negatives can occur in DUI testing in several ways:
- Breathalyzer errors: Breathalyzer tests are one of the most common methods for measuring BAC. However, these tests can be affected by external factors such as residual mouth alcohol, temperature, and other substances in the mouth. These factors can result in a false positive reading, indicating a higher BAC than what the individual actually has.
- Blood sample errors: Blood tests are considered more accurate than breathalyzer tests, but they are not immune to errors. False positives can occur if the blood sample is contaminated or mishandled during the testing process. False negatives can occur if the blood sample is not taken correctly or is not tested promptly.
- Field sobriety test errors: Field sobriety tests (FSTs) are physical tests that measure a driver’s coordination, balance, and ability to follow instructions. False positives can occur if the FST is not administered correctly or if the driver has a medical condition that affects their performance. False negatives can occur if the driver is able to perform the FST despite being under the influence of alcohol.
Overall, false positives and false negatives in DUI testing can have serious consequences, including wrongful arrests and convictions, as well as unsafe drivers remaining on the road. It is crucial for law enforcement agencies to ensure that the testing methods are reliable and accurate, and for drivers to be aware of their rights and the potential for errors in testing.
Field Sobriety Tests
As well as blood and breath tests, you may have to undergo field sobriety tests after being pulled over by police.
Purpose of Field Sobriety Tests
The purpose of field sobriety tests is to simply give the officers an idea of how intoxicated the individual may be. If an individual can’t perform basic tasks, like reciting the alphabet backward or standing on one leg, it’s usually a clear sign that they’ve got a certain level of alcohol in their system.
Common Field Sobriety Tests and How They Work
Some common field sobriety tests may include:
- Balancing on one leg.
- Walking along an imaginary straight line.
- Reciting the alphabet backwards or forwards.
- Solving a basic math problem.
- Following an object, like a pen, with your eyes.
Conclusion
As we can see, there are many myths around DUI testing, and many people take drunk driving less seriously because of some of those myths. We hope that this guide has helped to debunk some of the common misconceptions you may have around DUIs, as it’s important for everyone to be aware of the risks and realities of drunk driving and DUI testing.
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FAQs
How long can blood be stored for DUI? ›
Blood Alcohol Concentration in Expired and Non-Expired Approved Containers Stored at Room Temperature and Under Refrigeration for 21 Days.
How long should it take for DUI blood samples to come back? ›DUI blood samples sometimes come back within four to six weeks, but many tests can take more than six months before they are completed. The longer it takes to get your results back, the easier it may be for your drunk driving accident lawyer in Los Angeles, CA to question the validity of these tests.
How long does it take to get blood alcohol results back in a suspected DUI case in California? ›These independent findings are admissible in court and may prove your innocence in a DUI case. The DUI blood test results time is usually about four to six weeks, so make sure to plan accordingly when it comes to your court date.
Can a blood test for alcohol be wrong? ›False readings for blood tests frequently occur based on various factors. The most common reasons for a positive blood alcohol test include improper calibration of the equipment, administering the test too soon, blood alcohol rising, health conditions and medications, or contamination of the sample.
How long are blood samples good for? ›Whole blood can be stored at 4–8°C for up to 24 hours before the serum is separated, but it must not be frozen. Whole blood should be allowed to clot and then centrifuged at 1000 × gravitational units (g) for 10 minutes to separate the serum.
How long are blood tests stored? ›Laboratory Medicine
It is highly recommended blood samples should arrive in the laboratory within 24 hours of collection – the laboratory may not be able to process samples received after this time. Overnight storage of blood samples before dispatch to the laboratory is not recommended and actively discouraged.
Test results from an alcohol blood test may be available soon after the test is conducted. Patients may receive their results within a few hours to several business days.
Is it better to take a blood test or breathalyzer? ›Generally speaking, if you strongly feel that you are under the legal blood-alcohol content limit of . 08%, you will want to choose a blood test because it is more accurate. Breath tests have a larger margin for error. They can be skewed by mouthwash or other products that contain alcohol.
Does an alcohol swab affect a DUI blood test? ›If The Medical Technician Uses An Alcohol Swab On Me Before The Blood Test, Will This Affect the Test Results? Yes. This can contaminate your blood sample because alcohol swabs usually contain 2% ethyl alcohol.
What can cause your blood alcohol level to be high without drinking? ›There is limited information in the medical literature on auto-brewery syndrome, also known as gut-fermentation syndrome. This rare syndrome occurs because of yeast overgrowth in the gut, leading to fermentation of ethanol, thereby causing symptoms similar to alcohol intoxication without ingestion of alcohol.
Can you refuse a blood test for DUI in California? ›
When you are arrested for DUI, you will be ordered to take either a blood or breath test. Refusing this test is a normal response, but unfortunately, it's also illegal. This is because California law says that you agreed to take the test in advance—the day you got your driver's license.
How do you beat the BAC test? ›You can beat a breathalyzer by hyperventilating, exercising, or holding your breath before you blow. Fact: An often-cited decades-old study found that hyperventilation and vigorous exercise did indeed lower subjects' BAC readings by as much as 10%.
What can affect alcohol blood test? ›- Age. As you get older, the same drink boosts your BAC faster than in a younger person.
- Drink strength. Even different drinks in the same family, like two different beers, can have different amounts of alcohol.
- Food. ...
- Sex. ...
- Weight. ...
- Medicines and drugs. ...
- Race and ethnicity.
In contrast to a breath test, diabetes will not affect the accuracy of a result in cases where a blood test is used by police to determine a person's alcohol concentration. This is because blood tests specifically test for ethyl alcohol which is the impairment causing ingredient in all alcoholic drinks.
Does a blood test show more alcohol than a breathalyzer? ›Are blood tests more accurate than breath tests? Blood tests generally produce more accurate results than breathalyzers and other breath tests. Blood tests directly measure the suspect's actual BAC.
How many hours does the human blood sample becomes worthless? ›Specimens stored > 12 h. for CMP may generate unreliable results. For CBC, samples could reliably be stored for 24 h.
What do they do with your blood after they test it? ›After the blood sample has been taken, it'll be put into a bottle and labelled with your name and details. It'll then be sent to a laboratory where it'll be examined under a microscope or tested with chemicals, depending on what's being checked. The results are sent back to the hospital or to your GP practice.
Why do they take 4 vials of blood? ›A certain amount of blood is consumed to test for different items. A small amount can lead to inaccurate results or failure to produce results. Drawing an excessive amount of blood will ensure that there is enough for retesting in case of abnormal results.
How long do labs keep records? ›Clinical lab tests and reports are kept a minimum 5 years after the test.
What are the most common errors in specimen collection? ›Two of the most common errors that occur during specimen collection and handling are clotting and inaccurate volume. Exposure to temperature extremes may also cause specimens to be rejected for testing. Clotting compromises the integrity of a specimen, making it unsatisfactory for testing.
Do blood samples get lost? ›
Specimen lost/unusable, repeat test – Unfortunately very occasionally samples are lost. Sometimes there is a delay in samples reaching the laboratory which can affect the quality of the specimen making it unusable. Occasionally an incorrect test is requested in which case a repeat may not be needed.
What lab values indicate alcoholism? ›A blood alcohol level in excess of 300 mg/dL, a blood alcohol level of greater than 150 mg/dL without gross evidence of intoxication, or a blood alcohol level of greater than 100 mg/dL upon routine examination indicates alcoholism with a high degree of reliability.
How far back can a CDT test detect alcohol? ›Carbohydrate-deficient transferrin, known as “%CDT,” is a blood test to detect heavy alcohol use (five or more drinks a day) over the past two weeks.
What blood alcohol level is drunk? ›per hour, regardless of how many ounces you consume. Therefore, the faster you drink, the higher your blood alcohol level will be. * . 08.10 blood alcohol level is considered legally drunk.
Are breathalyzers accurate enough for to be used as evidence? ›The results of a breathalyzer, or similar breath test, are potentially admissible in court if all the required procedures were followed. But they can also be challenged if there is a reason to believe the results are not accurate.
Is a breathalyzer better than a urine test for alcohol? ›Although urine testing is more accurate than a breathalyzer, it's not without error. Urine tests can yield false or skewed results due to both external and internal factors. Medical procedures during testing must be followed to a T, and if they aren't the sample may be too contaminated to test.
Should you drink plenty before a blood test? ›Ideally, start drinking more fluids the day before your blood draw, and continue to drink water before you have your blood drawn. Excessive amounts aren't necessary; most sources ecommend that an adult drink 64 ounces of water per day for good health, which is more than adequate for having your blood drawn.
Are alcohol swab tests accurate? ›After 24 hours, alcohol is typically sufficiently metabolized and is no longer detectable in the saliva. This makes saliva alcohol testing a highly accurate way to test for very recent alcohol use.
Why do you need a second blood test? ›If a doctor asks you to have a repeat test it is usually because: The result was borderline or equivocal – so the clinician wants another sample to monitor the situation or to re-check.
Is it necessary to cleanse the puncture site with alcohol swab? ›To clean the skin before a vaccination or other injection, suggested standard practice according to the World Health Organisation (WHO) is to swab the injection site with a saturated 60% to 70% alcohol swab for 30 seconds, then let the area dry for another 30 seconds so that the alcohol doesn't enter the puncture and ...
What medications increase blood alcohol level? ›
This includes antibiotics, antidepressants, antihistamines, and medications for pain, anxiety, or sleep. Some of these may increase your BAC. Your last meal: If you drink on any empty stomach, alcohol gets absorbed faster into the bloodstream and can spike your BAC much quicker.
Do heavy drinkers have lower BAC? ›Alcohol is distributed in tissues according to water content. A person's weight and sex determine the total volume of body water and, therefore, the BAC after drinking a certain amount of alcohol. In general, the more a person weighs, the larger the volume of body water and the lower the BAC.
Why am I walking like I'm drunk? ›Losing your balance while walking, or feeling imbalanced, can result from: Vestibular problems. Abnormalities in your inner ear can cause a sensation of a floating or heavy head and unsteadiness in the dark. Nerve damage to your legs (peripheral neuropathy).
What is the blood alcohol limit for DUI in California? ›Blood Alcohol Concentration (BAC) Limits
It is illegal for you to drive if you have a BAC of: 0.08% or higher if you are over 21 years old. 0.01% or higher if you are under 21 years old. 0.01% or higher at any age if you are on DUI probation.
It is, in fact, better to refuse a field sobriety test. California law does not require you to take a field sobriety test. Your participation is voluntary, and the results will be detrimental to your DUI defense.
How can I clear my BAC fast? ›- Drink Coffee. Drinking a strong black coffee is sometimes suggested by helpful friends as a means of 'sobering up'. ...
- Take a cold shower. Standing under some cold water will shock your body into sobering up. ...
- Eat. ...
- Sleep. ...
- Exercise.
There is nothing a person can do to quickly reduce the blood alcohol concentration (BAC) level in their body. The liver needs time to filter blood and remove the alcohol from the system.
Does chugging water lower your BAC? ›Contrary to popular belief, nothing can lower BAC except time; coffee, cold showers, and chugging glasses of water will not help you sober up any faster. Curious what your BAC might be?
How do you pass a CDT blood test? ›How do you pass the DVLA CDT test? The only way to guarantee that you will pass a DVLA CDT test is to abstain from drinking alcohol in the four weeks prior to taking the test. This is because people who do not drink, or drink moderately, have lower CDT levels in their blood.
How long does it take alcohol to leave your system calculator? ›| Body System | Time in System |
|---|---|
| Blood | Up to 6 Hours |
| Breath | 12-24 Hours |
| Urine | 12-24 Hours; 72 Hours or more for newer test methods |
| Saliva | 12-24 Hours |
Can drinking alcohol the night before a blood test affect glucose? ›
In general, alcohol the night before should not affect your blood test results, Dr. Krajcik says. If you begin fasting 12 hours before the test (including alcohol), it will most likely be metabolized, as long as you keep it to a drink or two.
Can high blood sugar cause false positive on breathalyzer? ›That's right, if you have diabetes, you run the risk of blowing a false positive with an alcohol blood test. This could be due to the acetone in your breath.
Is blood test worse than breathalyzer? ›Blood tests generally produce more accurate results than breathalyzers and other breath tests. Blood tests directly measure the suspect's actual BAC. Breath tests only indirectly measure someone's BAC. Blood tests are also less susceptible to environmental factors that can skew the results.
How much blood alcohol compared to breath? ›The concentration of alcohol in breath is about 2.000 times less than in an equal volume of blood. It means that to compare BAC and BrAC, you need to multiply the concentration in breath by a factor, the blood-breath ratio (BBR).
Do DUI blood kits need to be refrigerated? ›Storage of the Blood Sample
If glucose is present in the blood, yeast can develop and eventually convert the glucose into ethanol. Keeping a sample refrigerated can typically prevent the fermentation from developing. However, this can become an issue if the samples were stored at room temperature.
According to the manufacturer's instructions for the reagent and analyzer, ethanol concentrations remains stable if the tubes are kept at room temperature (15-25 °C) for 2 days, at 2-8 °C for 2 weeks, or at -25 to -15 °C for 4 weeks (14).
Does alcohol ferment in blood? ›When blood decomposition occurs, the sample ferments and alcohol is created in the blood. In fact, a scientific study showed that a blood sample containing no alcohol can ultimately produce a BAC result of . 25 percent or higher after decomposition has occurred.
Does alcohol preserve blood? ›Ethyl alcohol-saline-sugar solutions preserve erythrocytes for at least 150 days; they are excellent preservatives for the agglutinogens.
What happens if blood samples are not refrigerated? ›Depending on the blood's future use, longer storage without refrigerated or frozen temperatures can jeopardize its viability. For example, if stored blood is used in a transfusion, the blood never regains the flexibility that it lost after the three-week mark unrefrigerated in storage.
Do blood kits expire? ›Yes. Your blood testing kits can expire, which is why we recommend using your kit within three months of purchase. The blood collection tubes contain a gel that stabilises your blood to keep it safe for testing during transportation to our partnered lab.
How do you keep blood samples cold? ›
The ideal temperature for blood samples is between two and eight degrees Celsius. The samples must be packed in an insulated container with a cold pack to maintain this temperature. Specimens that need to be transported at a colder temperature should also be accommodated.
What are the rules for storing blood? ›Whole Blood must be placed in storage at a temperature between 1 and 6 deg. C immediately after collection unless the blood is to be further processed into another component or the blood must be transported from the donor center to the processing laboratory.
Does the temperature affect your BAC? ›Air and Body Temperatures and Breathalyzer Results
Having a fever at the time you undergo a Breathalyzer test can result in inaccurate results, as well. On average, for every 1 degree that your body temperature is above normal, your BAC reading will increase by 8%.
This is called an autologous (aw-TAH-luh-gus) blood donation. Autologous means you donate your own blood so it can be stored and used for your transfusion if needed. You may also get donated blood from the blood bank. This means the blood you get during your transfusion is donated by another person.
How fast does alcohol evaporate from blood? ›How Fast Can You Sober Up? Alcohol leaves the body at an average rate of 0.015 g/100mL/hour, which is the same as reducing your BAC level by 0.015 per hour. For men, this is usually a rate of about one standard drink per hour.
Does BAC drop after blood draw? ›A person's BAC will drop during the final phase. A blood sample taken from a vein may be unreliable because it will provide lower than usual results during the absorption phase and higher than usual results in the elimination phase.
What is alcoholic content in blood? ›Blood alcohol level (BAC), is the amount of alcohol in your blood that develops from drinking beverages that contain alcohol. Levels can range from 0% (no alcohol) to over 0.4% (a potentially fatal level).
Does alcohol destroy DNA in blood? ›They found that acetaldehyde can break and damage DNA within blood stem cells leading to rearranged chromosomes and permanently altering the DNA sequences within these cells.
How do you purify blood after drinking alcohol? ›- Get Some Sleep. While sleeping late won't physically flush alcohol out of your system, it's a good step toward getting your body back to normal. ...
- Drink Lots of Fluids. ...
- Get Food In Your Body. ...
- Sweat the Alcohol Out.
Chronic excessive alcohol ingestion reduces the number of blood cell precursors in the bone marrow and causes characteristic structural abnormalities in these cells, resulting in fewer-than-normal or non- functional mature blood cells.