How a prosecutor in Michigan is able to admit the Datamaster or blood result against the defendant

In Michigan, a prosecutor will most likely have a BAC reading to prosecute a drunk driving case; the majority of the time, it will be blood or breath.  Although there is a print out of the result, this alone is not admissible at a trial against the charged party.  A prosecutor must admit the evidence into that trial following a very specific requirement list.  

Certain prerequisites must be met for chemical test results to be admissible. A prosecutor must demonstrate the following: 

• the qualifications of the person(s) administering the test,
• the method or procedure used to administer the test, and
• the reliability of the testing device (not the testing principle).

Although the prosecutor must demonstrate that proper procedures were followed, he or she is not required to affirmatively show compliance with every rule and regulation regarding breath tests and the qualifications of the person administering the test are determined by testimony that he or she is certified by the Michigan State Police to administer such tests.

Defense lawyers always run into the issue that the DataMaster operator is only supposed to be an operator, and he or she does not claim to be an expert on the workings of the instrument or on the scientific principles involved.  Operators like to avoid questions, play dumb and try to pass the responsibility off to the machine itself;  if approached correctly, this is VERY helpful for the case. A jury will be faced with the question of trusting a machine where the person operating it is simply throwing their hands up in the air and say "I don't know, but I just know". 

To prove the reliability of the testing device, however, the operator should be able to testify that the instrument was tested weekly by a certified DataMaster operator and inspected by the Michigan State Police at least once every 120 days, using controlled test samples furnished by the state police.  This testimony is a sufficient foundation for admitting test results. Alternatively, each facility with a DataMaster DMT should have a keeper of records who can testify to the weekly accuracy checks and 120-day inspections.