There are many common sources of error in the use of breathalyzers, devices designed to measure the amount of alcohol in an one’s breath. Homeostatic variables, i.e. the differences in biological makeup of individuals, can have a drastic effect on the results of a breath test.

The computers inside breathalyzers work by multiplying the amount of alcohol in an individual’s breath sample by a factor of 2,100 to arrive at that person’s blood alcohol concentration (“BAC”). The computer is programmed to assume that every tested individual has 2,100 units of alcohol in his or her blood for every one unit of alcohol in his breath, a calculation known as the “partition ratio”.

The use of the partition ration creates a problem, however, as it is only an average of the actual ratios exhibited by the general population which can range as low as 900:1 to as high as 3500:1. For example, assuming a person has an actual BAC of .07%, which is legal in Ohio, if that person has a partition ratio of 1500:1, he or she register a breath test reading of .10%, which is over the legal limit.

The bottom line: A person can fail a breathalyzer test merely because he or she is not average. Recent court decisions have opened the door to challenges regarding the use and accuracy of breathalyzers in Ohio.

If you have been charged with DUI/OVI, a knowledgeable attorney can help you protect your interests both in and out of the courtroom.

Scott Rubenstein, Cincinnati Attorney at Law