Testing the tests: blood sample fermentation as a DUI defense

Being taken into custody after an accident and having your blood sampled for possible DUI charges will naturally make you feel helpless, even if you’re sure you weren’t intoxicated — but the outcome of the blood test is not always the final word in the story.

In a Vermont criminal DUI case currently moving through the courts, a forensic pathologist consulted by the defense has raised new questions about the manner in which the driver’s blood was tested. Forensic pathologists are medical specialists who investigate the circumstances of sudden or accidental deaths.

In this case, the pathologist noted that the blood sample taken from the defendant shortly after the accident had not been stored in the proper manner. Blood samples must have preservatives added to them, or there is a risk that the blood will actually ferment, a chemical process which results in the production of alcohol.

In the story reported in the news article, the state police lab did not use the necessary preservative, so the pathologist testified that the sample’s blood alcohol level (higher than the legal limit) was not necessarily reflective of the defendant’s blood alcohol level.

There are many stringent regulations which apply to the manner in which blood must be collected and handled for DUI evidence. The irregularities discovered in this case are giving new hope to one man dealing with criminal charges in the wake of a tragic loss, and they also demonstrate the subtleties involved in mounting a knowledgeable DUI defense.

Scientific evidence can get a person convicted of drunk driving. Our DUI defense attorneys know that scientific evidence related to breath and blood tests, however, can also free a person of the threat of a criminal charge. It’s about knowing what questions to ask and what so-called “proof” to challenge.

Source:, “Forensic pathologist aids defense in fatal crash case” by Don Lehman, Jan. 21, 2013

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