How to Challenge a Breathalyzer Result in Court

Breathalyzer results are often seen as the gold standard in DUI cases, but they are not foolproof. Many people are surprised to learn that these machines can be challenged in court. If you’ve been charged with a DUI based on a breath test, understanding how to challenge the result could be the difference between a conviction and a dismissal.

What Is a Breathalyzer and How Does It Work?

A breathalyzer is a device that estimates blood alcohol concentration (BAC) by measuring the amount of alcohol in your breath. When you drink, alcohol is absorbed into your bloodstream and travels to your lungs. Some of that alcohol is exhaled, and the breathalyzer uses a ratio to convert the breath alcohol reading into a BAC estimate. That ratio is typically 2100:1, meaning 2100 milliliters of breath contains the same alcohol as 1 milliliter of blood.

But that’s an average. Real people vary. Your body temperature, breathing pattern, and even the presence of mouth alcohol can skew the results. That’s one reason why the defense may question the reliability of the test in your case.

Common Grounds for Challenging a Breathalyzer Result

There are several ways to attack a breathalyzer result. The key is to find a flaw in the evidence that creates reasonable doubt. Here are the most common approaches.

Calibration and Maintenance Records

Breathalyzer machines must be regularly calibrated and maintained to ensure accuracy. The state is required to keep records of these checks. If the records show the device was not calibrated on schedule, or if the maintenance log is incomplete, your attorney can argue the results are unreliable.

For example, if the machine hasn’t been calibrated in months, it could have been reading too high. A calibration error of even a few hundredths can push a borderline BAC over the legal limit. Defense attorneys often request these records early in the case. The prosecution may be unable to prove the machine was working correctly.

Officer Training and Certification

The officer who administers the breath test must be properly trained and certified to operate the specific breathalyzer model. If the officer’s certification is expired or if they lack the required training, that can be a basis to challenge the result. Your attorney can subpoena training records and test the officer’s knowledge on the stand.

Procedural Errors During the Test

There are strict procedures for administering a breathalyzer. The officer must observe you for a period before the test, typically 15-20 minutes, to ensure you don’t burp, vomit, or put anything in your mouth. That observation period is crucial because mouth alcohol can contaminate the sample. If the officer fails to follow the observation protocol, or if they don’t document it, the results may be challenged.

Other procedural errors include failing to use the correct mouthpiece, not calibrating the device each day, or not providing you with a second test. Many jurisdictions require two tests minutes apart. If only one was taken, that’s a red flag.

Medical Conditions That Can Affect Breathalyzer Results

Certain medical conditions can cause a breathalyzer to give a falsely high reading. Acid reflux, GERD, and diabetes are common culprits. These conditions can create mouth alcohol or interfere with the breath sample. If you have a condition that could affect the test, your attorney can present that evidence to the jury. It’s not a guaranteed win, but it can create doubt about the accuracy of the result.

Mouth Alcohol and the Observation Period

Mouth alcohol is one of the biggest causes of false positives. If you have any residual alcohol in your mouth from a sip of a drink, mouthwash, or even a cough syrup, it can spike the BAC reading. The officer’s observation period is designed to let mouth alcohol dissipate. If the officer didn’t watch you for the full time, or if you burped during the test, the result could be invalid.

Using the Evidence to Build Your Defense

Once you and your attorney identify a valid issue, the next step is deciding how to use it. The defense might file a motion to suppress the breathalyzer evidence altogether. If the court grants that motion, the prosecution loses a key piece of evidence, and the case often falls apart.

Alternatively, the defense can use the issue to negotiate a plea deal. A weak breathalyzer reading might persuade the prosecutor to reduce the charges to a lesser offense, such as reckless driving. That can save your license and your record.

In some cases, the defense brings in an expert witness. A forensic scientist who understands breath test technology can explain the error rate to a jury. Expert testimony can be very persuasive.

Step-by-Step: How to Challenge a Breathalyzer Result

1. Request the breathalyzer’s calibration and maintenance records from the court or the prosecutor.
2. Obtain the officer’s training and certification documents.
3. Review the police report for procedural mistakes or missing documentation.
4. Consult with a DUI attorney who can evaluate whether there’s a viable challenge.
5. File a motion to suppress the breath test evidence if there’s a strong legal basis.
6. If the evidence stands, consider an expert witness to dispute the reliability.
7. Negotiate with the prosecution or take your case to trial.

What If You Already Took and Failed a Field Sobriety Test?

Field sobriety tests are often used alongside the breathalyzer. They’re subjective and can be challenged too. If the breath test is weak, the field test results may be the only other evidence. But field tests are notoriously unreliable. Many factors—nervousness, poor lighting, physical conditions—can cause a innocent person to fail. A motion to suppress the field test evidence might also be possible if the officer didn’t follow standardized procedures.

The combination of challenging the breathalyzer and the field test can significantly weaken the prosecution’s case.

How an Attorney Can Help in a Breathalyzer Challenge

Challenging a breathalyzer result is a technical and legal process. The law requires strict compliance with rules about evidence and the admissibility of breath test results. An experienced DUI attorney knows these rules and knows what to look for in the records. They also know how to cross-examine the officer and any expert witnesses.

Attorney representation also helps you navigate licensing issues. A DUI conviction can lead to license suspension, but with a good defense, you might avoid that. Attorneys often work to protect your driving privileges.

Practical Tips for Your Case

Act quickly. In many states, you have a limited time to request a hearing to challenge the license suspension. Also, keep your own notes about the night of the arrest: what you ate, any medications you took, medical conditions, and how the test was administered. Small details can become important later.

Even if the breathalyzer challenge doesn’t get the case dismissed, it can lead to a better outcome. Many prosecutors are willing to reduce charges when the scientific evidence is questionable.

Understanding Implied Consent and Breathalyzer Refusal

When you get a driver’s license, you automatically agree to submit to a breath test if an officer suspects you of DUI. That’s called implied consent. Refusing the test can lead to an automatic license suspension, often longer than a DUI suspension. But refusing also means the state doesn’t have a breathalyzer reading. Some drivers find that a strategic choice, but it carries serious consequences.

If you refused, your attorney can focus on other evidence, like the officer’s observations or field sobriety tests. Those can still be challenged, but the stakes are different. It’s critical to know your state’s rules on refusal penalties and whether a refusal can be used as evidence against you.

Common Mistakes People Make When Challenging Breathalyzer Results

One mistake is missing the deadline for requesting a hearing. Another is trying to argue the science without expert help. A judge won’t buy a DIY explanation of calibration errors. You need a lawyer who can frame the issue within the law.

People also forget that they can question the accuracy of the breathalyzer machine itself. The manufacturer’s maintenance manual and the software update history can be valuable. An attorney can request those records too, if they exist.

Don’t assume the officer followed procedure just because they said so. The defense can request the dashcam video and any notes from the stop. A lack of documentation can be just as powerful as an outright error.

Remember: a breathalyzer result is evidence, not a verdict. You have the right to question it. If you’re facing a DUI, consult with an attorney who can investigate the facts and determine the best defense strategy. The effort you put in now can protect your future.

Frequently asked questions

Can I challenge a breathalyzer result if I was over the legal limit?

Yes. Even if your BAC was above the legal limit, you can challenge the reliability of the test. The defense may argue that the device was faulty, the officer made an error, or your physical condition affected the result. If the evidence is suppressed, the case may be dismissed or reduced.

How do I get the breathalyzer calibration records?

You can request them through the discovery process in your criminal case. Your attorney files a formal request to the prosecutor or the court. In many jurisdictions, the state is required to provide them if they plan to use the breath test at trial.

What does ‘mouth alcohol’ mean in a breathalyzer test?

Mouth alcohol is any alcohol still present in your mouth or throat at the time of the breath test. It can come from a recent drink, mouthwash, or even some medications. Residual mouth alcohol can falsely elevate the reading. Officers must observe you for a period to allow it to dissipate.

Can a medical condition like acid reflux invalidate a breathalyzer test?

Potentially, yes. Acid reflux (GERD) can bring alcohol vapor from the stomach into the mouth, which can cause a falsely high reading. Diabetes can also produce chemicals that may be mistaken for alcohol. An expert witness can explain this to the judge or jury.

What happens if the breathalyzer evidence is thrown out?

If the breathalyzer result is suppressed, the prosecution may still have other evidence, such as field sobriety test results, officer observations, or your own admission of drinking. However, without the BAC number, the case may be significantly weaker, leading to reduced charges or dismissal.