Articles Posted in Breath-Blood-Urine-Testing

Wikipedia defines Radio Frequency Interference as:

“Electromagnetic interference (or EMI, also called radio-frequency interference or RFI when in high frequency or radio frequency) is disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source.^[1] The disturbance may interrupt, obstruct, or otherwise degrade or limit the effective performance of the circuit. These effects can range from a simple degradation of data to a total loss of data.”

This article discusses RFI and breath testing machines.

For years defense lawyers and breath testing experts claimed that breath test machines (like the Intoxilyzer 5000) read other substances on your breath as alcohol and thus gave a false high reading. These substances are called “interferents.” Examples of interferents are paint fumes, carburetor cleaner, and substances found in many beauty salon supplies. For just as many years the the corporation that made the machines (CMI, Inc.) and the Maine’s breath test staff claimed that was just a defense lawyer’s gimmick. They said the machines were specific for alcohol, would reliably detect interferents, and would subtract any interferents from the final blood alcohol content (BAC) results reading.

So who was right? Was it a gimmick from a DUI lawyer? Were the people whose jobs depended on the machines being right covering something up?

A couple of year’s ago CMI came out with a new model, the Intoxilyzer 8000 alcohol breath testing machine. The State of New Mexico was an early buyer. Maine just bought about a hundred of them. The books CMI gave to New Mexico with the 8000 model said this about the old 5000 model:

I cannot tell you the number of people I talk to who say, “Well, the breath test says I blew over .08, so there is nothing I can do, right?” Wrong! What most people do not understand is that breath tests do not measure your blood alcohol level. Breath tests estimate your blood-alcohol level. They do that by using a lot of assumptions that assume everyone is the same. Do you really think everyone is the same? Hint: the answer is “no.”

This is Part I of a series of blogs about the assumptions that form the basis of breath testing, and why those assumptions are flawed. A breath test can be off, way off. While they are right much of the time, they are unfortunately wrong at the wrong times. As a result, innocent people are convicted of DUI.

I will start with explaining how breath testing is supposed to work. After that I will talk about the problems that occur. If there is something particular any reader would like me to comment on about breath testing, please let me know.