False Positives on Breathalyzer Tests

What foods can cause a false positive on breathalyzer tests?

A false positive on a breathalyzer test occurs when the test reports that the driver is intoxicated to the extent that he or she is over the legal limit, when in fact the driver has not consumed alcohol or has consumed a small amount. False positives are uncommon but do occur as a result of some medical conditions, foods, or issues with the breathalyzer machine. A false positive can be devastating to a driver, leading to an arrest, criminal charges, and potentially even conviction if the breathalyzer results are not properly attached. Our Phoenix criminal defense lawyers explore the causes of false-positive breathalyzer tests below.


Acetone can exist normally on one’s breath, and acetone can be read as alcohol by a breathalyzer test. At times, acetone levels can be high enough on a person’s breath to cause the breathalyzer to read the driver as over the legal limit. Diabetics tend to have high levels of acetone in their breath, particularly when their sugar levels are not well under control. This can lead to falsely inflated alcohol levels on a breathalyzer test.

Low Carb Diet 

Low carb diets are all the rave, but few dieters are aware that a rare risk with the diet involves a false positive on a breathalyzer test. Low carb diets like the Atkins diet or keto can cause the body to produce increased acetone levels as the body enters a state of ketosis. Ketones within the body produce isopropyl alcohol, which converts to acetone. As discussed above, acetone can be mistaken for alcohol by a breathalyzer test.

Poorly Calibrated Breathalyzer Tests

Police standards require that all breathalyzer tests be carefully calibrated to ensure accuracy. Unfortunately, not all officers will take the time to ensure their device complies with state and federal standards. A poorly calibrated breathalyzer test may falsely inflate alcohol levels, leading to arrests based on incorrect information. 

Drivers arrested on the basis of a breathalyzer test may wish to consider demanding a blood test if they believe the breathalyzer test produced a false positive. When in doubt, always contact a DUI attorney as soon as possible after your arrest to protect your legal rights. 

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