Understanding the Science Behind Breathalyzer Accuracy and Flaws

When it comes to DUI charges, accuracy is everything. But how reliable are breathalyzer test results? Our seasoned attorneys at Stechschulte Nell Law are here to demystify the inner workings of these controversial devices so that you can make informed decisions and fight back against unjust accusations. 


Whether you’ve been wrongfully accused or want to arm yourself with knowledge for future reference, understanding the intricacies of breathalyzer accuracy is crucial in mounting a strong defense.  



How Breathalyzers Measure Blood Alcohol Content 


The science behind breathalyzer technology is rooted in the basic principles of chemistry, particularly the reactions that occur when alcohol is consumed. 


A breathalyzer measures the concentration of ethanol, a type of alcohol, in an individual’s bloodstream, denoted as Blood Alcohol Content (BAC). 


The accuracy and efficacy of breathalyzer tests have been called into question, especially in legal disputes related to impaired driving.  


Chemical Reaction in Breathalyzer  


A breathalyzer works on the premise of the chemical reaction that occurs when alcohol comes into contact with chemicals present in the device. This reaction creates a measurable compound, providing a quantifiable indicator of the presence of alcohol.  


The main compound used in breathalyzers is typically chromium (VI) oxide, also known as potassium dichromate, an orange-colored compound that turns green when it reacts with alcohol. 


The process: 

  1. The subject blows into the device, which collects a sample of breath in a testing chamber. 
  2. A chemical reaction occurs with the potassium dichromate present in the breathalyzer. 
  3. The green color change is then measured to estimate the BAC. 


The Mathematics Behind the BAC Calculation  


The breathalyzer test results are then matched with an individual’s BAC through a coded mathematical equation, embedded within the device’s software. 


This equation takes into account factors such as the person’s: 

  • Sex 
  • Respiratory rate 
  • The temperature of their breath 


Complex data processing algorithms are used within the breathalyzer to swiftly carry out these intensive calculations. 


The Margin of Error: How Breathalyzer Results Can Be Inaccurate 


Notwithstanding their ubiquitous usage, breathalyzers do not always provide an incontrovertibly accurate estimation of one’s BAC. Calibration, physiological considerations, and external factors can dramatically skew results, leading to potential misinterpretations with severe consequences. 


  • Calibration Issues: Repeated use without regular, proper calibration can compromise a device’s accuracy. Even slight deviations from the expected ratio can spur inaccurate results. 
  • Physiological Considerations: Each person metabolizes alcohol differently. Factors like body weight, the rate of consumption, the presence of food, and individual metabolism rates can affect BAC readings. 
  • Operator Error: Inaccurate results often stem from improper administration of the test by law enforcement officers. 
  • Health Conditions: Certain medical conditions like acid reflux, diabetes, or hypoglycemia can falsely elevate BAC readings.  
  • External Factors: Certain mouthwashes or medications containing alcohol can yield a high BAC result, even if no actual alcohol has been consumed. 
  • Legal Protocols: Any deviation from the prescribed legal protocols during the administration or post-administration processing of the breathalyzer test can render results invalid. 


Considering these potential inaccuracies and flaws, it becomes clear that breathalyzer results should not be deemed irrefutable. In many cases, they provide only a general guesstimate of alcohol impairment and any perceived ‘evidence’ they present must be critically examined in a court of law. 


Read More > Discrediting Breathalyzer Test Evidence 


Can I Refuse a Breathalyzer in Florida? 


As an element of the state’s implied consent law, drivers in Florida do theoretically agree to a breathalyzer test if an officer pulls them over on suspicion of driving under the influence (DUI). However, the decision to decline a breathalyzer is not as clear-cut as it may initially seem. Multiple aspects play a role which, in turn, would lead to numerous consequences.  


Refusing the Test  


In Florida, refusal to submit to a breathalyzer test upon lawful request by a law enforcement official can lead to serious consequences. These include license suspension and mandatory DUI school, among other penalties. Furthermore, the fact of refusal can be used against the defendant in court to imply guilt. 


Necessity of Probable Cause 



It is paramount to remember that an officer cannot ask for a breathalyzer test without having probable cause. 


Probable cause refers to reasonable grounds for making a search, pressing a charge, etc., in the context of a DUI stop, the officer must have credible reason to believe the driver is under the influence.  


Probable cause can include: 

  • Erratic driving or traffic violations 
  • Evident alcohol or drug consumption 
  • Slurred speech, unsteady walking, or impaired coordination 


Understanding Your Rights  


As lawyers trained in this field, we suggest that if you are confident that you are not under the influence and that the officer does not have probable cause, then refusing the test might be an option. If you’re uncertain or uneasy about the situation, however, you should contact us for advice.  


  • Contact a lawyer immediately: Your lawyer can help ensure your rights are protected, and guide you through the process, whether you decide to take the breathalyzer test or refuse it. 
  • Stay calm and respectful: Agitation or disrespect might create further issues and result in more charges. 
  • Decline to answer incriminating questions: Anything you say can and will be used against you in a court of law. It is completely within your rights to refrain from answering any questions without an attorney present. 


Read More > 3 Types of Breathalyzers 


Skilled DUI Defense  


If you find yourself facing a DUI charge and are skeptical about the accuracy of a breathalyzer test, it is crucial to seek legal assistance immediately. At Stechschulte Nell Law, our experienced lawyers understand the complexities of DUI cases and can provide a thorough review of your case.  


We will examine all available evidence, including the breathalyzer results, to challenge their validity and build a strong defense strategy for you. Don’t wait, contact us today for a consultation, and let us fight for your rights.  


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