Should I Take a Blood or Breathalyzer Test if I'm Asked?

Being pulled over for suspected drunk driving can be extremely stressful. At the scene, the officer will likely ask you to take a preliminary breath test. If you’re arrested, they will conduct additional tests at the station to confirm your blood alcohol level. The result of these tests can carry lasting legal consequences.

This article looks at the key factors to consider when deciding whether you should consent to a breath or blood test. You have the right to refuse these tests, but there are consequences for doing so.

If you are facing DUI charges and aren’t sure what to do next, consult a DUI lawyer. They can help explain your rights based on your state laws and assist you with the following legal proceedings.

Is It Better To Take a Breathalyzer Test or a Blood Test?

State DUI laws allow law enforcement to make an arrest in one of two ways:

• Per se DUI: Where a person’s blood alcohol concentration (BAC) is above the legal limit, 0.08% in most states, or 0.05% in Utah, and they are assumed to be impaired.
• Impairment DUI: A person can still face DUI charges even if they are below the legal limit or refuse testing if there is additional evidence showing they were impaired by drugs or alcohol.

The penalties are the same for both. The most common way law enforcement finds probable cause to make a DUI arrest is by measuring a person’s BAC.

If you’ve been drinking, your BAC will vary based on many factors. These factors include:

• The amount of alcohol consumed
• Your sex
• Your body type
• How much time has passed since you consumed alcohol

The use of a breath test versus a blood draw to determine BAC largely depends on where you are in the process of a DUI arrest. Officers may use different types of breath testing devices at different stages of a DUI case:

• Preliminary breath tests (PBTs) are roadside screening tests in which officers use portable handheld devices to obtain an initial BAC reading.
• Evidentiary breath tests (EBTs) are tests that officers conduct at a police station after an arrest. These machines provide a more accurate measurement of BAC levels than handheld devices used by officers at the roadside stop.
• Blood tests are conducted by medical professionals post-arrest to provide more concrete evidence for the charges brought against the driver.

Understanding the difference between the different types of DUI tests is valuable when we’re discussing whether to consent to sobriety testing. Let’s take a closer look at what you might encounter.

Breath Tests

Both roadside BAC screening devices and station Breathalyzers measure the alcohol vapor in your breath to estimate your BAC levels. Although people often use “breathalyzer” to describe any breath testing device, Breathalyzer is a brand name for the machine often used at police stations after officers make an arrest. Your state or county might use Intoxilyzers or other similar machines.

Roadside preliminary breath tests offer an immediate result and help officers determine whether there’s probable cause to make an arrest. However, the results of PBTs often cannot be used as evidence in court.

In many states, you can legally refuse the roadside preliminary breath test without automatic license suspension penalties under implied consent laws. EBTs conducted at the station, on the other hand, produce more accurate results that are generally admissible in DUI legal proceedings.

Breathalyzer tests offer the most immediate results and are less invasive than blood tests, making them the preferred type of test for roadside testing. Breathalyzer readings are not as accurate as blood tests. Several factors can affect the test, which may lead to a false positive result.

Certain medical conditions, such as diabetes, are linked to the presence of acetone in breath. This could affect the breath test. Using things like mouthwash can also skew test results, but not in your favor.

Blood Alcohol Tests

In a DUI blood test, medical personnel draw blood from you so they can directly measure the blood alcohol level in your bloodstream. Blood tests are more accurate compared to breath tests. It is one of the most reliable methods of measuring the BAC level.

A blood test is more invasive and takes longer to return results than a breath test. Medical personnel or trained technicians draw blood and then take the blood sample for testing. These tests are generally performed after the police make an arrest for suspected DUI.

Law enforcement usually requires a warrant to force a blood draw. There are some circumstances where that’s not the case.

Should I Submit to a Breath Test?

Hopefully, you’ll never be behind the wheel of a car while under the influence of drugs or alcohol. If you’re reasonably confident you’re sober, submitting to a breath test will likely end the situation quickly and in your favor. There are times we all make unwise decisions, and you may not be sure if you’re above the legal limit of 0.08% BAC. Under the flashing lights of a police vehicle, you might think your best option is to refuse testing.

That’s not a guaranteed get-out-of-jail-free card. There are penalties for refusal. The consequence is typically an automatic driver’s license suspension. It also doesn’t stop officers from arresting you for DUI. They can still make an arrest based on other observable evidence of impairment, such as erratic driving or the smell of alcohol.

Can You Refuse a Breathalyzer and Request a Blood Test Instead?

In most states, you cannot simply refuse to undergo one test and demand another. The law enforcement officer often may choose what type of test to administer based on the circumstances.

For instance, in Maine, law enforcement officers should administer a breath test if they have probable cause to believe someone is driving under the influence. If the officer determines that a breath test is unreasonable, they may conduct another chemical test instead.

A breath test could be unreasonable under several circumstances, including:

• Medical conditions: If you have a medical condition that prevents you from providing an adequate breath sample, officers may accommodate a blood test or urine test request. This may apply if you have asthma or a lung disease.
• Equipment malfunction: If the breathalyzer is not functioning properly, the officer may conduct a blood test as an alternative.

Some states allow a person to ask for additional or independent tests at their own expense. This doesn’t allow them to choose which initial test the officer will administer. Independent testing is typically done to refute the findings by law enforcement.

Keep in mind that state laws vary. Some states require officers to inform a person of their right to refuse a breath test and the potential consequences if they do. For example, Washington state law requires officers to inform drivers of their right to refuse a breathalyzer test before they administer it. The law also requires officers to inform the driver that if they refuse to comply, they will lose their driver’s license for at least one year.

Other states emphasize the requirement for a driver to undergo testing. Colorado state law requires any driver to undergo a chemical test if an officer finds reasonable grounds that the driver is driving under the influence. The express consent laws in Colorado focus on the consequences if a driver does not comply with the DUI test. These consequences may include driver’s license revocation and mandatory treatment programs.

Due to these varying state laws related to DUI testing, consulting a DUI attorney after an arrest is a good move. They can provide legal advice tailored to your case based on the applicable state laws.

Implied Consent Laws

All 50 states have implied consent laws that assume drivers consent to blood alcohol testing if they are arrested on suspicion of driving under the influence. It’s usually necessary to agree to implied consent to be issued a driver’s license. If you’re driving on public roads, you consent to testing if you’re pulled over for a potential DUI.

This means that although you can refuse to submit to a BAC test, there are penalties for doing so. In most states, you risk at least a six-month suspension of your driver’s license. In some states, you can lose your license for up to a year.

These penalties are separate from any criminal penalties you can face if you’re convicted of a DUI. The state department of motor vehicles (DMV) can suspend your license immediately for refusal, even if criminal charges are never brought.

Implied consent laws may only apply to post-arrest chemical testing, not roadside screening tests. It will depend on the laws of the state in which you’re pulled over.

Forced Blood Draws

In some states, including Ohio and Texas, the decision to submit to testing can be taken out of your hands with the practice of forced blood draws by police officers. It’s not a common practice, but it’s available for law enforcement if you’re involved in a serious motor vehicle accident or there are other exigent circumstances. Whether or not forced blood draws are an option depends on your particular state.

In Missouri v. McNeely (2013), the U.S. Supreme Court ruled that officers should have a warrant for forced blood draws. An exception for a warrant only applies in exigent circumstances. This landmark case significantly changed how officers can conduct draws for blood tests. In most states, law enforcement officers should obtain warrants before conducting blood draws rather than relying on the state’s implied consent laws.

The Supreme Court’s decision in Birchfield v. North Dakota (2016) further distinguished blood draws from breath tests. The Court ruled that warrantless breath tests are allowed during a DUI arrest, but warrantless blood tests are not. The Court emphasized how breath tests are less intrusive than blood tests and that the criminal penalties for refusing a blood test are unconstitutional. States can still impose civil penalties.

This distinction was refined further in Mitchell v. Wisconsin (2019), where the Court considered situations involving unconscious drivers. It held that, in most cases, when a driver is unconscious and cannot consent, law enforcement may perform a blood draw under the “exigent circumstances” exception, but the specifics can depend on the facts of each case. Together, these cases define the balance between individual privacy rights and public safety in DUI investigations.

Other Evidence of Impairment

If you’re pulled over and an officer asks you to take a BAC test, your refusal alone will not be enough to avoid a DUI charge. They will consider any other evidence against you. That evidence can include:

• Field sobriety tests
• Erratic driving
• Physical signs of impairment, like slurred speech
• Open alcohol containers in plain site (in some states)

If an officer has other evidence, they can recommend a DUI charge without a breath test. In some states, prosecutors can use your refusal as further evidence of guilt.

There are very few circumstances where a refusal is a better idea than taking a BAC test. The only guaranteed way to avoid a DUI charge is to not drive while under the influence of alcohol or other substances.

Get Legal Advice From a Criminal Defense Attorney

Whether you choose to submit to a breath test or a blood test, it’s essential to understand the repercussions of a DUI conviction in your state. Learn more by speaking with a DUI defense attorney. A DUI defense lawyer can help you better understand DUI laws and ensure you get the best possible outcome for your DUI case.