As many know, a breathalyzer is a machine that police officers and prosecutors often use to measure a person’s blood alcohol level (BAC), when they feel a person is driving under the influence. How a breathalyzer works is, it takes a small sample of a person’s breath and estimates how much alcohol is in the sample. Then the officers and prosecutors use these results to estimate how much alcohol is in a person’s blood. In the state of Arizona, the legal limit of a person 21 years and older is a BAC of 0.08%. If a person is asked to perform a breath analysis test and the machine records the person’s BAC as over the legal limit, then they will be arrested and prosecuted for DUI, and the breathalyzer results could become central to the prosecution’s case.

However, scientists have recognized an inherent error in breath analysis. Generally they agree that there is a margin of error of plus or minus .01%. That means if the machine is functioning properly, a reported result of 0.1% could actually be anywhere from a 0.09% to a 0.11%, a range of 20%. This range is considered acceptable by police and crime laboratories across the country.

There are numerous other factors which also contribute to the potential inaccuracy of the machine and its results. Primarily, the machine must be properly maintained and calibrated by the police. Additionally the officers must administer the test correctly. The result can also be affected by a person’s physical condition. If any of these factors are off it could affect the accuracy of the machine’s results and ultimately whether a person is charged with a DUI.

In most professions, a 20% margin of error is unacceptable, especially when someone’s life or liberty is on the line. Certainly you would not trust a doctor, accountant or pilot who has a 20% margin of error. Unfortunately, in relation to DUI cases, the prosecution can use these inaccurate results against a defendant in an attempt to put them in jail.

This is why if you or anyone you know gets charged with driving under the influence, you need an experienced DUI defense attorney to help defend your case. Call us, (480) 248-7666, or register for a free consultation at the Rosenstein Law Group. We are certified in DUI cases and will work hard to make sure your rights are not being taken advantage of.