Call 24/7 | 702-DEFENSE (702-333-3673)

Breath Tests in DUI Cases in Nevada

Las Vegas Drunk Driving Defense Lawyers

The DUI breath tests machines used by Nevada police are prone to getting it wrong. This can cause innocent people to get falsely arrested on Las Vegas drunk driving charges.

Below we explain what breath tests are, how they factor in Nevada DUI situations, and how it may be possible to get the breath test results excluded from evidence.

Our Las Vegas criminal defense attorneys are experienced in challenging the reliability of breathalyzers and their results, so contact us today at 702-DEFENSE (702-333-3673) for a free consultation!

What are breathalyzers?

In Nevada, driving with a blood alcohol content (BAC) of .08 or above is per se illegal. Breathalyzers are small devices that police agencies such as the Nevada Highway Patrol and Las Vegas Metropolitan Police use to measure the BAC of people whom they suspect to be driving under the influence or with too much alcohol in their system.

Unlike Nevada DUI blood tests, breathalyzer tests are largely painless and non-invasive procedures: The suspect blows into the breath machine, which then uses an internal aqueous solution of ethanol to analyze the breath and estimate the person's BAC. The type of breathalyzer Las Vegas cops typically use is the CMI Inc. Intoxilyzer 5000EN.

How are breathalyzers used in Nevada DUI arrests?

Drivers suspected of DUI in Las Vegas usually submit to two separate breath tests:


  1. A preliminary breath test (PBT) that takes place on the road shortly after they were pulled over, and


  2. an evidentiary breath test at the police booking station following their arrest.

Each test is different and serves a distinct purpose.

Preliminary Breath Test (PBT)

When you're first pulled over on suspicion of DUI in Las Vegas, the police will probably ask you to answer some questions, to perform field sobriety tests and to submit to a preliminary breath test (PBT). This is also called a roadside breath test or preliminary alcohol screening (PAS), and it's meant to give the police officer an initial idea of whether you're under the influence or not.

If you refuse to submit to a PBT in Las Vegas, the police will suspend your license and arrest you for DUI. If your case goes to trial, the PBT results may come in as evidence to show the police had "reasonable grounds" to arrest you. But it can't be used to show that you were driving under the influence. (NRS 484C.150)

Evidentiary Breath Test

If you're pulled over on suspicion of DUI in Nevada and fail the PBT or field sobriety tests, the cop will probably arrest you for driving under the influence and take you down to the police station. You are then legally required to submit to an evidentiary breath test (which is supposedly a more sophisticated and reliable test than the PBT), and the results can be used against you in court to show that your BAC was .08 or above.

Similar to Title 17 in California, Nevada law outlines strict rules that police must follow when administering an evidentiary breath test and analyzing the results. Just a few of the regulations include the following:


  • No more than two hours can elapse between the time of driving and the breathalyzer test.


  • The cop is required to observe you for at least fifteen minutes prior to administering the breathalyzer test to make sure you don't vomit, burp, belch, regurgitate or do anything else that can skew your breath.


  • The breath test must be administered two times right after each other, and the two BAC readings can't differ by more than .02.


  • The breathalyzer machine needs to have been properly maintained and calibrated.


  • The police officer needs to be certified to administer the breathalyzer.

Are breathalyzers ever wrong in Nevada DUI cases?

Yes, all the time! That's why it's vital you retain a drunk driving defense attorney in Nevada to uncover any and all evidence suggesting that your breathalyzer was either defective, unreliable or mishandled in your Las Vegas DUI case.

Depending on the facts of your case, your attorney may explore the following procedural, environmental, or physiological defenses when fighting a DUI charge:

Procedural Defenses


  • The breathalyzer device or aqueous solution inside was not calibrated or maintained properly.


  • The cop who administered the breathalyzer was not certified.


  • The cop administered the test outside of the two hour post-arrest window, or the cop didn't observe the fifteen minute observation period prior to giving the test.

Environmental Defenses


  • Radio frequency interference (RFI) may cause a breathalyzer to skew the BAC results.


  • Your breathalyzer was broken or otherwise non-functional. (Breathalyzers usually employ either infrared spectroscopy and/or fuel cell technology, which converts the quantity of alcohol in your breath to the quantity in your blood. This conversion often causes compromised results and inaccurate readings.)


  • Breathalyzers are believed to have margins of error of up to .02; so, for example, someone with a .09 BAC reading may actually be under the legal limit.

Physiological Defenses


  • You suffer from such conditions as GERD, heartburn or acid reflux, all of which can "fool the machine" and cause a falsely high BAC reading.


  • You had alcohol in your mouth ("mouth alcohol"), which masked the deep lung air (alveolar air) that Nevada breathalyzers are meant to measure for DUI purposes.


  • You had a rising blood alcohol level, which tends to cause the machine to exaggerate or over-report your true BAC level.


  • You were on an Atkins-style low carb / high protein diet at the time, which auto-produces isopropyl alcohol. This can "trick" the breath machine, causing it to read a high BAC even if you've had little or nothing to drink.

As you can see, numerous factors can cause a breathalyzer to give falsely high readings. So it's of utmost important that you tell your attorney everything you can remember regarding the DUI incident, your medical history, your diet, your health, even what you ate or drank that day . . . something you think is irrelevant may be the key to fighting a Las Vegas DUI case.

If your attorney can cast doubt on the accuracy of your breath test, then he/she might get it excluded as evidence. And once the BAC results are excluded, the prosecution should be more willing to reduce the drunk driving charge to a less serious offense or to throw it out completely.

Can I refuse to take a DUI breath test in Nevada?

Anyone who drives in Nevada is considered to have given "implied consent" to submit to both a preliminary breath test and an evidentiary breath test. And if a policeman asks you to take an evidentiary breath test and you refuse, he can use "reasonable force" such as constraining you to compel you to take a blood test instead. (NRS 484C.160)

If you do refuse to submit to a DUI breath test, the prosecution may introduce your refusal as evidence...and ask the judge to construe it as an indicator that you were driving under the influence in Nevada. Refusing to submit to an evidentiary test will also cause your driver's license to be suspended for one to three years.

Blood tests

If you're arrested for DUI in Nevada, you can request to have your blood drawn instead of taking a breathalyzer test. But since it's a more complicated procedure, they will charge you money for it if a working breathalyzer was readily available.

Independent Testing

If you're arrested for DUI in Nevada, you can always request that a qualified chemical tester of your choosing administer an independent test of your blood. Having an independent chemical tester is useful because it may show discrepancies between the two tests' results and can cast light on any protocol violations or other mistakes the police may have made. (NRS 484C.180)

We're here to help . . . .

If you've been arrested for DUI in Nevada, you're invited to contact our Las Vegas drunk driving defense lawyers at (702) DEFENSE for a free phone consultation. Whether you took a breath, blood or urine test, we're skilled in all the ways to try to exclude the results from evidence so your DUI charge may get reduced or dismissed completely.

For information about DUI breath tests in California, go to our article on DUI breath tests in California.

    • translate
    Nevada DUI Law Explained.....
    Call Us for Help | 702.333.3673

    If you or a loved one faces misdemeanor or felony charges, contact our Las Vegas NV criminal defense attorneys at (702) DEFENSE. We'd be glad to meet with you for a free consultation. We practice throughout Nevada, including Las Vegas, Henderson, Reno, Carson City, Boulder City, Mesquite and Laughlin.

    Client Reviews

    5 A Powerful, Effective Advocate to Have in Your Corner

    In my time of need I called on Neil Shouse and his law firm. It was one of the best decisions I've made in my life. Not only did he step up to assist me, he went the extra mile in every sense of the word. I found Neil to be honest, professional, and tireless in his efforts on my behalf.

    -


    Recently, I made a stupid decision to drink and drive. I was caught speeding in the rural town of Moapa Nevada. I was pulled over and arrested for DUI. My blood alcohol was high and I was nervous about the consequences that could come from the court in that area. Michael took care of my entire case and had my DUI reduced to a reckless driving. This was a huge relief and I am astounded at his work and talent. I also have to compliment his staff, mainly Case Manager John Eisele for being so helpful.

    - Michael S, a DUI client


    I've used Michael for several of my personal tickets, but have reffered all criminal matters to him do to his experience in the Criminal Defense field. All my friends always thank me because he gets excellent results. Michael is a great attorney and dedicated to his clients.

    - Chris, a DUI client


    Michael has helped me with my legal battles for many years. The one thing that always sticks out to me is his honesty and concern for his clients. He has helped us in so many ways, and given jobs to felons who would have otherwise been turned away. Michael is an exceptional human being, and his compassion and care for his clients is top notch. If you have any doubts about his abilities just sit back and watch him work. He is a Master in that courtroom.

    - Scott, a DUI client

    If you'd like further assistance...

    Join us to discuss your DUI case at any of our
    local offices: You can also contact us 24/7 at
    702-DEFENSE for a free consultation

    Las Vegas Office:
    2300 W. Sahara Avenue
    Suite 450
    Las Vegas, NV 89102
    (702) 333-3673

    Reno Office:
    9190 Double Diamond Pkwy
    Reno, NV 89521
    (775) 348-9685

    Copyright © 2012 - Nevada DUI Defense Lawyers - Las Vegas Criminal Defense Attorneys - All rights reserved.

    Nevada Drunk Driving Defense Attorney Disclaimer: The DUI Defense, Drunk Driving, DMV Drivers License Suspension, Driving Under the Influence, Driving While Intoxicated or other DUI defense information presented at this site should not be considered formal legal advice nor the formation of a lawyer or attorney client relationship. Any results set forth here were dependent on the facts of that case and the results will differ from case to case. Please contact a Nevada DUI defense lawyer or attorney for a free initial consultation. This web site is not intended to solicit clients for matters outside of the State of Nevada.

    We employ Copyscape Premium. Any republishing of copyrighted material without the express written consent of the publisher is prohibited. Such plagiarism is illegal, constitutes professional misconduct and constitutes an infringement of the Digital Millennium Copyright Act.

    Sitemap | California Criminal Defense Lawyers | Español |

    Page copy protected against web site content infringement by Copyscape