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  • Writer's pictureWilliam Matthews

Breathalyzer Accuracy and Potential Challenges: Navigating Court, Orlando DUI Attorney

Updated: Aug 23, 2023


Breathalyzer tests have become a staple in law enforcement's toolkit for identifying and prosecuting individuals driving under the influence of alcohol. These portable devices are designed to measure blood alcohol concentration (BAC) through a person's breath. However, as with any technology, the accuracy of breathalyzer tests and their reliability in court proceedings have sparked debates and concerns. In this blog post, we will delve into the intricacies of breathalyzer accuracy and explore the potential challenges that defense attorneys might raise regarding their reliability in legal proceedings. It's important to hire an Orlando DUI attorney as soon as possible.

Understanding Breathalyzer Accuracy

Breathalyzer devices, often referred to as alcohol breath testers or alcohol analyzers, work based on the principle of infrared spectroscopy or electrochemical reaction. The basic premise involves measuring the amount of alcohol present in a person's breath and converting it into an estimated BAC level. While these devices are widely used by law enforcement agencies, questions about their precision and accuracy have arisen.

Calibration and Maintenance

One of the primary challenges to breathalyzer accuracy lies in their calibration and maintenance. Breathalyzer devices require regular calibration to ensure their readings are consistent and reliable. Failure to calibrate or maintain these devices properly could lead to inaccuracies in BAC measurements. Defense attorneys might argue that a lack of proper calibration could raise doubts about the accuracy of the readings obtained during an arrest.

Individual Variation

Individual variations in physiology can also impact the accuracy of breathalyzer tests. Factors such as metabolism, body temperature, and respiratory conditions can influence the results. Defense attorneys could potentially argue that an individual's unique physiological characteristics might lead to a skewed reading, making it crucial to account for these variables in court proceedings.

Mouth Alcohol Contamination

Mouth alcohol contamination occurs when residual alcohol remains in the mouth, leading to an elevated BAC reading. This can result from recent alcohol consumption, the use of mouthwash, or even certain medical conditions. Breathalyzer devices are designed to measure deep lung air, which is a more accurate representation of BAC. However, defense attorneys might assert that the presence of mouth alcohol could lead to inaccurate readings and question the reliability of the test results.

Rising Blood Alcohol Defense

The "rising blood alcohol" defense is based on the concept that an individual's BAC may continue to increase after being pulled over by law enforcement. This occurs because alcohol takes time to be absorbed into the bloodstream. Defense attorneys could argue that a person's BAC was below the legal limit at the time of driving but exceeded it by the time the breathalyzer test was administered.

Potential Challenges in Court

  1. Technical Malfunctions: Breathalyzer devices are electronic devices prone to malfunctions. Defense attorneys might raise concerns about the reliability of a specific device if it has a history of technical issues or if it was not properly maintained.

  2. Operator Error: The accuracy of a breathalyzer test can be compromised by errors made by the law enforcement officer administering the test. Defense attorneys might question the officer's training, expertise, and adherence to proper procedures.

  3. Lack of Chain of Custody: Proper handling and maintenance of evidence are critical in legal proceedings. If there are gaps in the chain of custody for the breathalyzer device or the test results, defense attorneys might challenge the integrity of the evidence.

  4. Medical Conditions: Individuals with certain medical conditions, such as acid reflux or diabetes, may produce breath samples that differ significantly from those without these conditions. Defense attorneys could argue that such medical conditions render the breathalyzer results unreliable.


Breathalyzer tests play a crucial role in identifying and prosecuting drunk drivers, but their accuracy and reliability can be subject to scrutiny. Potential challenges raised in court proceedings emphasize the need for a comprehensive understanding of the technology, proper calibration, and adherence to standardized procedures. As technology continues to evolve, addressing these challenges will be vital to maintaining the credibility of breathalyzer tests in legal cases involving driving under the influence. Hire an Orlando DUI attorney as soon as possible. If you have been charged with any criminal offense, give Matthews Criminal Defense a call today at my Orlando, Florida office at (407) 561-8166 for a free consultation.

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