When a defendant is arrested on suspicion of driving under the influence, he or she will be asked to submit to chemical testing. They will be provided a choice of a breath test that can be completed at the police station using a Breathalyzer device or a blood test that would be conducted at the station or at a hospital where a blood sample would be withdrawn and would be subject to analysis. The blood test is often considered to be the more accurate form of testing, however there are several issues that can be used to challenge the integrity of blood testing.
How a blood sample has been stored and cared for is critical to the integrity of the sample. Many crime labs have backlogs of samples to analyze and as a result blood samples may be left out in the open for days before being processed. However, because a blood sample is composed of organic material, it will begin to decompose as a result of enzymes and various bacteria. When blood decomposition occurs, the sample ferments and alcohol is created in the blood. In fact, a scientific study showed that a blood sample containing no alcohol can ultimately produce a BAC result of .25 percent or higher after decomposition has occurred.
Because of this, most properly stored blood samples will be kept refrigerated. It is important to remember that refrigeration will not prevent decomposition, but will delay the process. In order to prevent the blood sample from decaying and producing alcohol, it is necessary to add a preservative such as sodium fluoride to the blood sample. If the lab failed to store the sample properly or failed to add a preservative, the defendant may be able to challenge the integrity of the blood sample.
Most labs use test tubes containing 20 mg of sodium fluoride as a measure to preserve the integrity of the blood sample. Some scientists have challenged whether this is a sufficient amount of preservative to ensure that fermentation does not occur and have suggested that at least 100 mg of sodium fluoride should be added to a sample. However, when sodium fluoride is added to a blood sample, the reported blood alcohol level can go up in labs that use gas chromatography to analyze the samples. The amount of alcohol detected can increase by approximately 9% in these situations.
The risk of blood fermentation will depend on the type and amount of preservative used, the length of time that a blood sample is stored and the temperature at which a sample is kept. Fluctuations in storage temperature have been shown to significantly increase the risk of blood fermentation. Even in blood samples that contain sodium fluoride preservative, Candida albicans can be produced. Candida albicans is a microbe that is most commonly responsible for alcohol production in stored blood samples, even those that contain preservative, when the sample is left at room temperature for an excessive amount of time.
Whenever a blood sample is collected, an anticoagulant is typically added to the sample to prevent the sample from coagulating and being unusable. The type of chemicals and solutions used in the anticoagulant may also affect the alcohol content in the blood sample.
Once the blood has been analyzed, the sample will be stored as evidence. The defendant can request a blood split that would allow part of that sample to be sent to a laboratory for independent testing. However, it is important to remember that any fermentation or decay that may have occurred would be still be present in the sample released to the independent lab and may therefore produce a similar BAC result when retested.
If you have been charged with driving under the influence and have provided a blood sample for testing, it is critical that you discuss your case with a Los Angeles DUI Attorney immediately. As a former Deputy District Attorney with over 14 years of prosecutorial experience, Attorney Michael Kraut understands the science behind DUI blood analysis and knows how to effectively challenge blood test results. Mr. Kraut often works closely with top experts in the field to ensure his clients are properly defended.
For more information about DUI and blood fermentation, and to schedule your free consultation, contact Michael Kraut at the Kraut Criminal & DUI Lawyers located at 6255 Sunset Boulevard, Suite 1520, Los Angeles, CA 90028. Mr. Kraut can be reached 24/7 at 888-334-6344 or 323-464-6453.