Because every officer in Oakland County uses the Datamaster DMT in their drunk driving investigations, understanding the various issues that routinely come up with it is vital to a successful cross examination of the officer. One such issue is when the machine indicates that it believes that there is "interference" in the breath test sample. What this means is that the Datamaster DMT machine believes that the sample breath blown into the machine contains a substance other than alcohol.
There are all sorts of things that could interfere with the test. Saliva, stomach contents, and many other things could find their way into the breath test machine. When we see interference printed on the ticket, we believe it is a major red flag to the accuracy of the test. The remedy we generally advocate to the jury is that the officer should have obtained a blood draw because there was something wrong with the machine.