"Breath Tests" in Nevada DUI Cases

Implied consent to take breath tests

Nevada DUI suspects may be required to submit to two breath tests to measure their blood alcohol content (BAC):

  1. the preliminary breath test (PBT), which motorists take at the side of the road to determine whether they will be arrested for DUI; and
  2. the evidentiary breath test (EBT), which a suspect takes only after getting arrested for DUI.

Only the EBT breath test results are admissible as evidence if the case goes to trial. 

Refusing to take the breath test

Refusing to take the PBT will result in the police officer confiscating the suspect's driver's license and arresting him/her for DUI. 

DUI arrestees who refuse to take the evidentiary breath test face a 1-year driver's license revocation and can be forced to submit to an evidentiary blood test.

Defenses against breathalyzer results

Common arguments to challenge breath test results include:

A skilled Nevada criminal defense attorney may be able to get the breath test results excluded from evidence.

In this article, our Las Vegas DUI defense attorneys discuss:

Nevada DUI suspects give "implied consent" to submit to breathalyzer tests.

1. What are breathalyzers in Nevada DUI cases?

Breathalyzers are mechanical devices that measure people's blood alcohol content (BAC) through their breath. Police agencies such as the Nevada Highway Patrol and Las Vegas Metropolitan Police use breathalyzers on people suspected of having driven under the influence of alcohol. Driving with a BAC of .08 or higher is per se illegal.1

Breathalyzers usually employ infrared spectroscopy and/or fuel cell technology. The devices convert the quantity of alcohol in the defendant's breath to the quantity in the defendant's blood. This conversion often causes compromised results and inaccurate readings.

Unlike DUI blood tests, breath tests are largely painless and non-invasive: The suspect blows into the breathalyzer, which then uses an internal aqueous solution of ethanol to analyze the breath and estimate the person's BAC. Also unlike blood tests, breathalyzers cannot detect drugs -- only alcohol.

1.1. How the breathalyzer works


The type of breathalyzer Las Vegas police use on DUI arrestees is the Intoxilyzer 8000. It is manufactured by CMI, Inc., in Owensboro, Kentucky. And it was approved for use in Nevada by the Nevada Committee for Testing on Intoxication.

The Intoxilyzer 8000 uses a two-filter wheel infrared (IR) spectrometer to detect organic vapors in a breath sample. Although it takes about 20 minutes to warm up, the device has a "standby" mode that permits it run continuously without depleting its resources. 

Unlike previous models which had a pressure switch, the Intoxilyzer 8000 uses a flow sensor. In order for the flow sensor to work, the following four conditions must be met:

  1. The defendant blows no less than 1.1 liters of air into the tube;
  2. The defendant blows continuously for no less than one (1) second;
  3. The alcohol concentration slope starts to plateau;
  4. The pressure reaches about 50 psi.

Finally, the BAC results get printed on paper. An example of the printout from the Clark County Detention Center is above/ to the right.2

1.1.1. Technical info

The machine uses the "Dry Gas Standard" to conduct control tests during the breath test sequence. The correct gas concentration is 0.08 g/210L with an acceptable range from 0.075 to 0.085  g/210L. When any analysis result falls outside of the acceptable range, the machine displays CONTROL OUTSIDE TOLERANCE.3

Below is the "checklist" that Nevada police must complete when administering an evidentiary breath test on people arrested for DUI of alcohol:

breathalyzer checklist

2. What is the difference between preliminary breath tests and evidentiary breath tests in Nevada DUI cases?

Drivers suspected of drunk driving in Las Vegas may be asked to take two separate breath tests:

  1. A preliminary breath test (PBT) that takes place on the road shortly after they are pulled over, and
  2. an evidentiary breath test (EBT) that takes place at the police booking station following their arrest.

Each test is different and serves a distinct purpose:

2.1. Preliminary Breath Test (PBT)

breath test

When DUI suspects are pulled over in Nevada...or when police arrive at the scene of an accident where DUI is suspected...the police will probably ask the suspects to do three things:

  1. take out their driver's license and registration,
  2. perform field sobriety tests, and
  3. submit to a preliminary breath test (PBT).

The PBT is also called a roadside breath test or preliminary alcohol screening (PAS). It is meant to give the police officer an initial idea of whether suspects are under the influence of alcohol or not.

If the case goes to trial, PBT results may come in as evidence to show the police had "reasonable grounds" for arrest. But PBT results cannot be used to show that a defendant was driving under the influence.

Motorists suspected of DUI in Nevada are legally required to submit to a PBT. When suspects refuse to submit to a PBT, the police will confiscate their license and arrest them for DUI.

Note that if the police arrest a DUI suspect prior to giving the PBT, the police may not then give the suspect a PBT without his/her consent to take it or without a warrant (or valid warrant exception). Otherwise, the PBT may qualify as an unlawful police search.4

2.2. Evidentiary Breath Test (EBT)

Motorists arrested for DUI in Nevada are legally required to submit to an evidentiary breath test (EBT) or blood test. (If the police believe the suspect is high instead of drunk, the suspect must submit to a blood test.)

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. The regulations include the following:

  • No more than two (2) hours can elapse between the time of driving and the breathalyzer test.
  • The officer is required to observe the defendant for at least fifteen (15) minutes prior to administering the breathalyzer test. This is to make sure the defendant does not vomit, burp, belch, regurgitate or do anything else that can skew the breath results.
  • The breath test must be administered two (2) times right after each other, and the two BAC readings cannot differ by more than .02.
  • The breathalyzer needs to have been properly maintained and calibrated.
  • The police officer needs to be certified to administer the breathalyzer.5

Unlike PBT results, EBT results can be used against DUI defendants in court to show that their BAC was .08 or above.6

3. Am I required to take breath tests in Nevada DUI cases?

Legally, yes. And there are dire consequences for refusing...

Anyone suspected of driving under the influence in Nevada is considered to have given "implied consent" to take a preliminary breath test. And if the suspect gets arrested for DUI, the suspect is considered to have given "implied consent" to take an evidentiary breath or blood test.

Note that DUI suspects are expected to submit to an evidentiary blood test if the police suspect them of driving while impaired by drugs. This is because breathalyzers cannot detect controlled substances.

Nevada law imposes various consequences for refusing to take a preliminary or evidentiary breath test:7

Type of Breath Test Consequences for DUI suspects who refuse to take a breath test

Preliminary breath test (PBT)

  • The officer confiscates the suspect's driver's license.
  • The officer will arrest the suspect.
  • If the case goes to trial, the prosecutor may introduce as evidence that the defendant refused the PBT.

Evidentiary breath test (EBT)

  • The police must get a warrant to administer an evidentiary blood test. Then the officer may use "reasonable force" to accomplish the blood draw.
  • The DMV will revoke the person's license for one (1) year. (The revocation period increases to three (3) years if the defendant already had a license revocation in the previous seven (7) years for refusing to take an evidentiary test.) The DMV will impose this revocation even if the person ultimately passes the blood test and the DUI charge gets dismissed.
  • If the case goes to trial, the prosecution may introduce as evidence that the defendant refused the EBT.

3.1. Blood tests

People arrested for drunk driving in Nevada can elect to take a blood test instead of a breath test. Since taking blood is a more complicated procedure than using a breathalyzer, DUI defendants who choose the blood test have to pay all associated costs if:

  1.  a working breathalyzer was readily available, and
  2.  the defendant is ultimately convicted of DUI

Note that if police believe the arrestee is under the influence of drugs, the defendant must take a blood test instead of a breath test.8

4. How accurate are the breathalyzers that Las Vegas police use?


Not very accurate considering so many variables unrelated to alcohol can cause false positives. (Scroll down to the next section for a list of some of these variables.) 

One problem stems from the manufacturer's refusal to share the Intoxilyzer 8000's source code. The manufacturer claims it is a trade secret, but hiding the source code precludes researchers from running comprehensive tests on the machine's efficacy. Just in the last few years, judges in Florida, Oklahoma, and even Ontario, Canada have ruled that the Intoxilzer 8000 cannot be trusted.9

That is why it is vital defendants retain a drunk driving defense attorney to uncover any and all evidence suggesting that their breathalyzer was defective, unreliable or mishandled in their Nevada DUI case.

5. How can breathalyzer results be challenged in Nevada courts?

Depending on the facts of the defendant's case, a criminal defense attorney may explore the following procedural, environmental, or physiological defenses when fighting a DUI charge:

Ways to challenge breathalyzer results in Nevada DUI cases Possible strategies

Procedural defenses

  • The breathalyzer device or aqueous solution inside was not calibrated, inspected, or maintained properly.
  • The officer or breath test technician who administered the breathalyzer did not have proper training or was not certified.
  • The officer administered the test outside of the two (2) hour post-arrest window.
  • The officer did not observe the fifteen (15) minute observation period prior to giving the test.

Environmental or mechanical defenses

  • Radio frequency interference (RFI) caused the breathalyzer to skew the BAC results.
  • The breathalyzer was broken or otherwise non-functional.

Physiological defenses

  • The defendant suffers from such conditions as GERD, heartburn, diabetes, or acid reflux. These conditions can "fool the machine" and cause a falsely high BAC reading.
  • The defendant had alcohol in his/her mouth ("mouth alcohol"), which masked the deep lung air (alveolar air) that Nevada breathalyzers are meant to measure.
  • The defendant experienced rising blood alcohol, which caused the breathalyzer to register a higher BAC than he/she actually had while driving.
  • The defendant was on an Atkins-style low carb/ high protein diet at the time, which auto-produces isopropyl alcohol. This can "trick" the breathalyzer into showing a high BAC even if the defendant had little or nothing to drink.

Therefore, numerous factors can cause a breathalyzer to give falsely high readings. Consequently, defendants should tell their attorney everything they can remember regarding the DUI incident: Medical history, diet, health, even what they ate or drank that day. Something that seems irrelevant may be the key to fighting the charge.

If a criminal defense attorney can cast doubt on the accuracy of the breath test, then the court might exclude it as evidence. And once the BAC results are excluded, the prosecution should be more willing to reduce the drunk driving charge to reckless driving or to throw it out completely.

702-DEFENSE (702-333-3673)
Call our Las Vegas drunk driving attorneys at 702-DEFENSE for a FREE consultation.

We are here to help

If you have been arrested for DUI in Nevada, you are invited to contact our Las Vegas criminal defense attorneys 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.

Arrested in California? Go to our article on DUI breath tests in California.

Arrested in Colorado? Go to our article on DUI breath tests in Colorado.

Legal References

  1. NRS 484C.110.
  2. See, e.g., Intoxilyzer 8000 Reference GuideFlorida Department of Law Enforcement Alcohol Testing Program (2006).
  3. Id.
  4. NRS 484C.150. Implied consent to preliminary test of person's breath; effect of failure to submit to test; use of results of test. See also State v. Sample, 134 Nev., Advance Opinion 25 (2018) ("Because the PBT was not administered pursuant to a warrant or an exception to the warrant requirement, we conclude that the district court properly suppressed the PBT evidence as an unconstitutional search.").
  5. NAC 484C.100-.120; NRS 484C.200; see Nevada DUI Prosecution Manual (2014).
  6. NRS 484C.160. Implied consent to evidentiary test
  7. NRS 484C.150; NRS 484C.160; NRS 484C.240.
  8. NRS 484C.160.
  9. Sean Lavin, Breath tests banned from courtrooms in DUI cases, ClickOrlando.com (July 31, 2014); Dan Karpenchuk, Ontario court finds common breathalyzer inaccurate, opening legal can of worms, WBFO 88.7 (May 17, 2016); Krystle Sherrell, Breathalyzer Tests Dismissed As Evidence In Oklahoma DUI Cases, KFSM 5 News (September 28, 2016).

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