Fermentation in CA DUI Blood Test Samples:

By otmseo on August 24, 2020

Problems With the CA DUI Blood Test: Fermentation and Contamination.


The first problem with blood testing for alcohol is that it’s impossible to tell how much alcohol was created by later fermentation of the sugars in blood by microorganisms. In other words, the microorganisms naturally present in the blood begin to produce alcohol in the sample.

Chemical Model of DUI Blood Test Fermentation

After the cops draw your blood, it is stored for up to a month. Microorganisms convert glucose (sugar) to alcohol. Candid Albicans and Saccharomyces Ellipsoideus, and other microbes that occur naturally in your blood, cause this. Fermentation is the process that turns sugar into alcohol. Fermentation is a fancy name for eating.  Microorganisms eat the sugar, remove energy from the sugar and leave carbon dioxide and alcohol as waste products. Studies show that over .20% BAC can be produced in improperly stored samples.

In court, the State can’t prove that the sample only contains alcohol present before the blood was taken from the body.  When the chromatograms of the blood tests are reviewed it is often shown that acetaldehyde is present. Acetaldehyde is a precursor to alcohol produced in the microorganism fermentation process  after the blood is taken. If acetaldehyde is present, we know alcohol is being made.

Problems with Storage.

Once collected, the state is supposed to store the sample at or near freezing (32 F). They are supposed to test the blood within 7 days to minimize fermentation. This is rarely, if ever, done.The sample is usually stored for 4 weeks, unrefrigerated.

A preservative/anti-coagulant is supposedly added to blood drawn by the cops, but no lab in California tests for the presence of preservative/anti-coagulant.  So we never know if it was present in the proper amount or if it was properly distributed in the sample. In fact, breweries add the preservative supposedly used by law enforcement to their beer to ensure that only the right microorganism ferments their beer.

The peaks of the chromatagrams may show contamination. A proper peak is symmetrical and shows only alcohol. An improper peak is broad or has a front or tail that is not symmetrical. An improper peak is evidence of contamination in the sample.  It means that there is more than one volatile organic compound in the tube at the same time and not only alcohol.  So the test reads higher in alcohol than it really is.That means that the State can never prove what the BAC is because the amount that is coming out that is alcohol can never be determined.


The cops can contaminate the sample. They do this when, they don’t draw blood in accordance with accepted medical practices.  Simply using a non-alcohol sterilizing agent on the area where the blood is drawn is not enough to prevent contamination.  Improperly sterilizing the area can cause contamination.

If you’ve been arrested for DUI and took a blood test, call me 213-479-5322 to discuss fighting and winning your case.

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