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Were you recently charged with DUI in Colorado because you failed a breathalyzer test? Don’t panic. You may not realize this, but breathalyzers are notoriously inaccurate. Simply getting a reading that puts you over the legal limit is no guarantee that you will be convicted.


In this post, we’ll explain the many reasons that breathalyzers can produce false positives, and how a skilled attorney can defend you against your Colorado DUI charge.


Faulty Machinery


Two types of breathalyzer machines are used by police to measure blood alcohol levels. A platinum fuel cell breathalyzer produces the most accurate results. Other breathalyzers use semiconductor sensors, which are not as accurate.


Tin oxide is the power agent for semiconductor sensors, and it responds to ketones in the breath. However, these are natural bi-products of digestion in general, which means that the readings that show up on tests can include more than just alcohol, skewing the results.


Bottom line? Breathalyzer machines that use semiconductor sensors are fine for personal use, but simply not accurate enough for evidence in a criminal case.


Improper Procedures


The person administering the test must follow proper procedure to get accurate results. This means that they must know not only how to operate the machine, but also correctly instruct you on how to blow into it the right way. Additionally, a test needs to be repeated so that consistency of results can be checked.


If the arresting officer did not follow all these procedures exactly and use proper technique, the tests could be wrong.


Mistakes in Calibration


Breathalyzers are sensitive machines that need regular, careful calibration to work properly. If the machine used in your test was improperly calibrated, it may have produced inaccurate results.


For example, the temperature setting must be constant. If it is off by only one degree, it can overestimate alcohol levels by up to 8.6 percent. Correct calibration is essential for test accuracy.


Health Conditions


If you have certain diseases, your results may be inaccurate. Any disease that produces excess mucus can produce higher alcohol levels in a breathalyzer test. Chronic conditions like asthma, emphysema, or fibrosis can reduce lung capacity and produce inaccurate results.


Diabetes is known to cause acetone to show up in breathalyzer tests, which will read as a false positive. Acid reflux can also produce false results due to the acids that move upward in the digestive tract. Any person who eats a high amount of protein can also have acetone on their breath, which a breathalyzer may read as alcohol.


Another health condition that affects breathalyzer test accuracy is the ratio of red blood cells in the blood. If your ratio is naturally higher or lower, the breathalyzer will not take that into account, and the results can be wrong.


Presence of Foreign Substances


Mouthwash is a commonly used substance that contains high levels of alcohol. Because of this, even if you use it correctly, it can produce a false positive result. Other substances in cough syrup, cigarettes, and hairspray can also show up in a breathalyzer test and lead to false positives.


One last one that few people take into account. If your airbag deployed before your test, the particulates released by the airbag may have entered your lungs. Why does this matter? You guessed it: because these particulates are known to throw off test results.


Environmental Factors


Maybe it wasn’t a specific, individual foreign substance linked to a particular instance, such as using mouthwash. Even if you were just in the area of certain chemicals before your breathalyzer test, it is possible that they can show up as alcohol.


Denver DUI Lawyer


Certain cleaning products, plastics, paint, adhesives, and lacquers have fumes that can mimic alcohol on a test and throw off the results.


What all of this means is that you should never plead guilty just because you tested positive on a breath test. They are not unbeatable, but you’re going to want to work with an experienced Denver criminal attorney can knows how to help you fight the charges produced by a false positive. Many other clients have had their cases dropped due to breathalyzer issues. Get in touch with us today for a free consultation.




About the Author: 


Kimberly Diego is a criminal defense attorney in Denver practicing at The Law Office of Kimberly Diego. She obtained her undergraduate degree from Georgetown University and her law degree at the University of Colorado. She was named one of Super Lawyers’ “Rising Stars of 2012” and “Top 100 Trial Lawyers in Colorado” for 2012 and 2013 by The National Trial Lawyers. Both honors are limited to a small percentage of practicing attorneys in each state.  She has also been recognized for her work in domestic violence cases.

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