Yes, breathalyzers are accurate when they are properly maintained and administered, but Arizona DUI defendants can still challenge the results produced by a breathalyzer. Your lawyer can argue that improper calibration, medical conditions, or testing errors impacted the outcome.
After all, the accuracy of breathalyzers is not absolute. While these devices are often introduced as evidence in DUI cases, that does not always mean that the number reflected by the device is beyond dispute, especially if you have a Phoenix criminal defense lawyer by your side.
Are Breathalyzers Always Accurate?
No, breathalyzers are not always accurate, even though they are widely used in DUI investigations. These devices are designed to estimate blood alcohol concentration through a breath sample, but estimation is not the same as certainty.
A number of outside factors can affect the final number reported by the machine. Breathalyzer results can be questioned when the testing device was not properly maintained or when the officer did not follow required procedures.
A short observation period, improper calibration, or contamination in the breath sample may create problems with reliability. In some cases, a result may be challenged because the reading does not reflect your actual blood alcohol concentration at the time of driving.
What Can Affect the Accuracy of Breathalyzers?
Several factors can affect breathalyzer accuracy, and some of them have nothing to do with how much alcohol you actually consumed. The device measures alcohol on your breath, so anything that changes the sample or the testing conditions can alter the result.
That is one reason DUI cases often involve close review of how the test was handled. Common issues that may affect a breath test include problems with the machine, user error, and physical conditions that interfere with the sample.
Some people have acid reflux, dental work, or other conditions that may leave residual alcohol in the mouth. Timing also matters, because alcohol absorption can continue after driving and before testing.
How Does Calibration Affect Breathalyzer Accuracy?
Calibration affects whether a breathalyzer is reading samples within an acceptable range, so it plays a direct role in the reliability of the result. If the machine is out of calibration, the reported number may be higher or lower than it should be.
That issue can become central when the test result is close to a legal threshold. A machine used in DUI enforcement should be checked, maintained, and documented according to the rules that apply to the device and agency.
When records are missing or show irregularities, the defense may question whether the machine was working properly on the date of the arrest. A problem with calibration does not always make the result unusable, but it may reduce the weight the court gives it.
Can Police Mistakes Make a Breathalyzer Result Unreliable?
Yes, police mistakes can affect the result of a breathalyzer, and any mishandling of the device can question if the results can be trusted. Even if the machine itself is functioning, the result may still be questioned if the officer did not follow the required testing steps.
Procedure matters because a breath test is only as reliable as the method used to obtain it. Before giving a breath test, officers are often required to observe the person for a set period to watch for burping, vomiting, eating, drinking, or placing anything in the mouth.
If that step is skipped or shortened, the sample may be affected by residual alcohol rather than deep lung air. The officer may also make mistakes when instructing the person, recording the result, or operating the machine.
Are Breathalyzer Results Enough to Prove a DUI?
No, breathalyzer results alone are not always enough to prove a DUI beyond dispute. Prosecutors often rely on the test result along with driving behavior, officer observations, field sobriety testing, and other evidence.
A breath test may be an important piece of the case, but it is usually not the only one. The strength of the evidence may depend on when the test was given and whether the state can connect the reported alcohol level back to the time of driving.
If there was a delay between the traffic stop and the test, the result may not show your alcohol concentration at the actual time you were behind the wheel. That timing issue can matter when alcohol is still being absorbed.
What Should You Do if You Doubt the Accuracy of a Breathalyzer?
If you doubt the accuracy of a breathalyzer, you should act quickly to preserve information that may help your defense. DUI cases often involve technical records and time-sensitive evidence, and delays can make those materials harder to obtain.
A prompt review may help identify whether there are issues with the stop, the arrest, or the testing process. After an arrest, it may help to write down what happened before and after the test, including whether you burped, felt ill, used mouthwash, or noticed long delays.
You may also want to note what the officer told you and whether you were watched continuously before the sample was taken. Small details can matter when a case turns on procedure and timing, and a lawyer can review them on your behalf while building your defense strategy.
Contact Suzuki Law Offices to Further Discuss the Accuracy of Breathalyzers
If you are facing DUI charges based on a breathalyzer test, it is important to remember that these devices are not infallible and that every detail of your case matters. At Suzuki Law Offices, RJ Suzuki is a former Assistant United States Attorney and former federal prosecutor.
Together, our attorneys have decades of experience handling cases involving breathalyzers throughout the state of Arizona. Our team approaches every case with diligence, integrity, and compassion because we understand how overwhelming criminal charges can feel.
We’re always available to answer your questions, protect your rights, and serve as your voice in action when you need it more than ever. When you’re looking for legal counsel you can trust, Suzuki is your lawyer.
Call or text (602) 682-5270 or complete a Free Case Evaluation form