What Can Cause a False Breathalyzer Result?

Breathalyzers don’t actually measure the blood alcohol content of your body—they measure the blood alcohol content of someone who is not on a diet, who has a normal level of blood sugar, and has a body temperature of exactly 98.6 degrees. These are the settings that breathalyzers are calibrated for, and they represent the “average” DUI suspect.

However, not everyone fits that description, which means your results may not actually reflect your true blood alcohol content.

False readings for breathalyzers can be caused by:

●Medications containing menthol

●Higher body temperature (fever)

●High blood sugar (acetone in the breath)

●Alcoholic mouthwash

For example, taking mouthwash prior to a breathalyzer test can result in a .07% reading on its own. While the mouthwash’s effects quickly dissipate, combined with a minimal amount of alcohol in your body could cause a false reading above the legal limit of .08%. For diabetic suspects, acetone is a side-effect of high blood sugar, and it can result in a false reading as well.

One study from the Journal of Forensic Science tested the BAC of a subject sitting in hot water with a blood test and a breathalyzer test. The breath test yielded a much higher result than the blood test, indicating that breathalyzers could be affected by elevated body temperature. If you have a fever, body temperature combined with medicine might result in a wrongful DUI charge.

All of this is assuming the device is calibrated correctly. False readings can be equally the fault of poor maintenance or poor calibration of the machine. If you’ve been arrested for driving under the influence, contact the Concord DUI defense attorney at The Law Offices of Darrin M. Gamradt, P.C. His experience in criminal defense cases, both as a prosecutor and defense lawyer, makes him uniquely qualified to handle your DWI/DUI case. Contact the firm today to get started.