"Breath Tests" in DUI Cases in Nevada
Explained by 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.

What are breathalyzers?

Driving with a Nevada 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.

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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 are 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 is meant to give the police officer an initial idea of whether you are 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 cannot be used to show that you were driving under the influence. (NRS 484C.150)

Evidentiary Breath Test

If you are 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 do not 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 cannot 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.
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Are breathalyzers ever wrong in Nevada DUI cases?

Yes, all the time! That is why it is 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 did not 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, diabetes, acid reflux, all of which can "fool the machine" and cause a falsely high BAC reading. Learn more about diabetes as a DUI defense in Nevada.
  • 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 in Nevada, 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 have had little or nothing to drink.

As you can see, numerous factors can cause a breathalyzer to give falsely high readings. So it is 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 get a warrant and use "reasonable force" such as constraining you to compel you to take a blood test instead. (NRS 484C.160) Furthermore, failing to submit will also cause your driver's license to be suspended for a year.

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

Independent Testing

If you are 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)

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We are here to help . . . .

If you have been arrested for DUI in Nevada, you are invited to contact our Las Vegas drunk driving defense lawyers at (702) DEFENSE (702-333-3673) for a free phone consultation. Whether you took a breath, blood or urine test, we are 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 the Nevada DUI defense of necessity, see our page on the Nevada DUI defense of necessity. For information about DUI breath tests in California, go to our article on DUI breath tests in California.




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