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 present at the time of the blood draw and 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.
What happens while the blood is stored is that the glucose (sugar) naturally occurring in the blood is converted by microorganisms (Candid Albicans and Saccharomyces Ellipsoideus, among others), through the process of fermentation, to alcohol. Fermentation is a fancy name for eating. These 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.
When the blood is drawn, if it is not done by accepted medical practices, the sample can be contaminated. 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.
Even if the area of the blood draw is properly sterilized, microorganisms present in the blood can cause fermentation.
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.
Once collected, the sample is supposed to be stored at or near freezing (32 F) and the test is supposed to be performed with 7 days to minimize fermentation. This is rarely, if ever, done.The sample is usually stored for 4 weeks, unrefrigerated.
Another problem is that the sample can never be proven by the State to contain only 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.
In addition to the fermentation that takes place post-draw, there can also be further contamination that can be seen in the peaks in chromatograms. A proper peak is symmetrical and shows only alcohol. An improper peak is broad or has a front or tail that is not symetrical. 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.
Read more about How Blood Testing Works.
Why Blood Testing is now the implied consent test that I recommend is discussed in my article ” Blood Test or Breathalyzer? Which test should I take?”
If you have questions about blood tests, their problems, which test to take or DUI in general:
We’re here to fight for you. Free Consultation. Call me at (213) 479-5322.
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28 Jun 2014
How the CA DUI Blood Test Works.
As part of the California Implied Consent Law, a person arrested for DUI is given the option of taking a breath or a blood test. For reasons I discuss elsewhere, blood testing is now my recommended choice.
Remember: unless you are under 21 or on DUI probation you are free to refuse the handheld Breathalyzer given at the scene of the DUI stop AND I advise that you so refuse.
When you opt to take a dui blood test, the cop takes you to a hospital, or in some cases they take you to a phlebotomist (vampire) that they have on staff at the police station. The blood drawer is supposed to draw the blood by using accepted medical practices.
The cop then takes the blood vial and puts it in an envelope. He puts the envelope in the unrefrigerated evidence room. At some point, the blood sample is moved to the crime lab. The blood is tested at the lab. It usually takes 3-4 weeks before the lab technician gets around to testing the blood. This creates a problem in that the blood becomes contaminated and the sample is ruined by fermentation. I discuss fermentation here: Fermentation: The Big Problem with the DUI Blood Test in CA.
When it is finally time for the actual blood testing, the lab technician takes the vial and uses a syringe to draw off two 1 millimeter samples. The samples are then put in an oven and heated. The gas above the blood in these samples is called the headspace. Once heated, the lab tech takes a syringe and draws off a very small sample of the headspace gas. This gas is then transferred to the gas chromatagraph.
To this gas a constant amount of Isopropanol is added. The Isopropanol is used as a baseline reading. A carrier gas, usually hydrogen, is used in the tube.
The science behind blood testing relies on headspace gas chromatography flame ionization detection. Gas chromatography is a process by which the various volatile organic compounds present in the gas sample are separated and measured. The gas is injected into a tube. The different volatile organic compounds take different amounts of time to go through the tube. For instance, in the sample chromatogram linked to below, ethyl alcohol (ETOH) comes through at 0.85 minutes.
Diagram of a Chromatogram Reading (Notice in the diagram linked to there are two peaks to the left of the alcohol peak. These are other volatile organic compounds in the sample that inidicate that (1) this sample is contaminated and (2) the blood has fermented after it was drawn. The peak farther to the left, at about 0.64, is the injection peak which shows when the sample was injected into the tube.)
There are two samples,and in the better method of blood testing, two different tubes are used so that it takes each of the volatile organic compounds a different amount of time to go through each tube (the amount of time it takes to go through the tube is called elution). When only one tube is used, you can’t tell whether the different volatile organic compounds are interfering with the measurement of alcohol no matter how many times you run the sample through (when two different substances come through the tube in the same time, this is called co-elution).
At the end of the tube, there is a flame. When the alcohol (ETOH) comes through the tube it is burned off and the increased ionization is measured. The hydrogen carrier gas has a base ionization rate. When the various organic compounds come through, the increased ionization is measured. The measurement creates a spike. As I discuss elsewhere, a good spike is symmetrical. A bad spike is not symmetrical or has a long foot at one side. The one linked to above has an asymmetrical foot on the right side. The spike doesn’t resolve to the base line until almost 1.0 minute.
The area under the spike is measured using calculus. The numerical value is the amount of alcohol in the blood which is then translated into grams/210 milliliters. A more sciency explanation can be found here.
This is how blood is tested. There are big problems with blood testing that you can use to fight your DUI case, which I discuss in my article Fermentation: The Big Problem With Blood Tests.
If you have questions about blood tests, it’s problems, which test to take or DUI in general call me at (213) 479-5322 or fill out the easy form at the right. I’ll be happy to give you a Free Consultation or answer ny questions you have. And if you have an opinion, please leave a comment.