Can You Challenge a DUI Blood Test Because of Improper Storage or Handling in California?
A DUI blood test is not necessarily reliable simply because it shows a blood alcohol concentration (BAC) above the legal limit. Mistakes in the collection, storage, transportation, or analysis of a blood sample can affect the reliability of the results. In some cases, these mistakes may provide important grounds for challenging the prosecution's evidence.
If you have been arrested for DUI in Chico, Butte County, or elsewhere in Northern California, an experienced criminal defense attorney can examine whether law enforcement and the testing laboratory followed the procedures necessary to produce reliable blood alcohol evidence.
How Are DUI Blood Samples Collected in California?
When someone is arrested for driving under the influence, law enforcement may obtain a blood sample to determine the amount of alcohol or drugs in the driver's system.
California regulations establish procedures for collecting and analyzing forensic blood samples. These requirements are designed to minimize contamination, preserve the sample, and promote accurate testing.
Under Title 17 of the California Code of Regulations, forensic alcohol testing is subject to specific standards. These include requirements relating to blood collection, preservatives, anticoagulants, and analytical procedures.
For example, blood samples intended for alcohol analysis must be collected using appropriate procedures to avoid introducing alcohol or other contaminants into the sample.
Failure to follow these procedures can raise questions about whether the reported BAC accurately reflects the driver's blood alcohol concentration at the relevant time.
Can Improper Storage Affect DUI Blood Test Results?
Yes. The manner in which a blood sample is stored can be an important issue in a California DUI prosecution.
Blood is a biological substance that can undergo changes after collection. Depending on the condition of the sample, the presence of microorganisms, the effectiveness of preservatives, and the storage environment, these changes can potentially affect alcohol testing.
1. Fermentation and the Production of Alcohol
One concern involving improperly preserved blood samples is fermentation.
Certain microorganisms, including yeast and bacteria, can produce ethanol under appropriate conditions. If a blood sample becomes contaminated and the conditions permit fermentation, alcohol may be produced after the blood has been removed from the person's body.
This raises an important question: Did the laboratory measure alcohol that was actually present in the driver's bloodstream, or was some alcohol produced after the sample was collected?
Fermentation does not occur in every blood sample, and improper storage does not automatically mean a sample has fermented. Nevertheless, the possibility of post-collection alcohol production may warrant investigation when there are indications of contamination, inadequate preservation, or unusual storage conditions.
2. Improper Refrigeration
The temperature at which a blood sample is stored can also be relevant.
Refrigeration can help limit microbial activity and preserve the condition of a biological sample. When a blood sample is exposed to elevated temperatures or stored under questionable conditions, the defense may have grounds to investigate whether the sample remained suitable for accurate analysis.
A DUI defense attorney may examine:
Whether the blood sample was refrigerated after collection.
How long the sample remained unrefrigerated.
Whether the sample was exposed to excessive heat during transportation.
Whether the laboratory maintained appropriate storage conditions.
Whether records document how the sample was handled before testing.
Importantly, a period without refrigeration does not automatically establish that a blood alcohol result is inaccurate. The significance of the storage conditions depends on the circumstances and the available scientific evidence.
3. Problems With Preservatives and Anticoagulants
Blood collection tubes used for forensic alcohol testing generally contain substances intended to preserve the sample and prevent clotting.
For example, sodium fluoride is commonly used as a preservative, while potassium oxalate may be used as an anticoagulant.
These substances serve different purposes. Preservatives help inhibit microbial activity, while anticoagulants prevent blood from clotting.
Potential issues include using an inappropriate collection tube, failing to follow the required collection procedures, or failing to properly mix the blood with the additives.
An attorney may investigate whether the correct tube was used, whether it was within its expiration date, and whether the laboratory documented any abnormalities in the sample.
What Happens if Police or the Laboratory Mishandle a Blood Sample?
A DUI blood sample typically passes through several hands before it is analyzed.
The sample may be collected by a medical professional, transferred to a law enforcement officer, transported to an evidence facility, and ultimately delivered to a forensic laboratory.
Each transfer creates an opportunity for mistakes.
Chain of Custody Problems
The chain of custody refers to the documentation establishing who collected, possessed, transported, stored, and analyzed the evidence.
Potential problems include:
Missing documentation concerning the transfer of the blood sample.
Inconsistent identification numbers or labeling.
Unexplained gaps in the evidence records.
Improperly sealed collection containers.
Questions about whether the sample tested was the sample collected from the defendant.
Not every chain-of-custody irregularity makes blood evidence inadmissible. However, significant problems may undermine the reliability or authenticity of the evidence and provide grounds for challenging the prosecution's case.
Does a Violation of Title 17 Automatically Invalidate a DUI Blood Test?
No. This is an important distinction under California law.
Although Title 17 establishes standards governing forensic alcohol testing, a violation of those regulations does not necessarily require exclusion of the test results.
In People v. Williams (2002) 28 Cal.4th 408, the California Supreme Court explained that noncompliance with Title 17 does not automatically make chemical test evidence inadmissible.
Instead, regulatory violations may affect the weight and credibility of the evidence.
This means that a defense attorney can use violations of testing procedures to challenge the reliability of the prosecution's evidence, even when the court permits the blood test results to be introduced at trial.
For example, if a blood sample was improperly preserved or stored, the defense may present expert testimony explaining why those circumstances could undermine the reliability of the reported BAC.
The prosecution may then be required to confront legitimate scientific questions about the accuracy of its evidence.
Can a DUI Blood Test Be Challenged Even if the BAC Was Above .08?
Absolutely.
California Vehicle Code section 23152(b) generally prohibits driving with a blood alcohol concentration of 0.08 percent or greater.
However, a laboratory report showing a BAC above 0.08 does not necessarily establish that the defendant was at or above that concentration at the time of driving.
A defense attorney may investigate several issues, including:
Accuracy of the testing process: Was the sample properly collected, preserved, and analyzed?
Measurement uncertainty: How close was the reported result to the legal limit, and what uncertainty is associated with the laboratory's measurement?
Timing of the blood draw: How much time elapsed between driving and collection of the sample?
Rising blood alcohol: Was the defendant's blood alcohol concentration still increasing after driving?
Laboratory procedures: Did the laboratory follow appropriate quality-control procedures, calibration requirements, and analytical protocols?
These issues may be particularly significant when the reported BAC is close to 0.08 percent.
For example, a blood test showing a BAC of 0.09 percent may warrant careful examination of measurement uncertainty, collection procedures, and the timing of the test.
Even when the reported BAC is substantially higher, a defense attorney should evaluate whether the evidence was obtained and analyzed reliably.
Can an Improperly Handled Blood Test Lead to a DUI Dismissal?
Potentially, depending on the facts.
If the blood test is a critical component of the prosecution's case, demonstrating serious reliability problems may significantly weaken the evidence.
Depending on the circumstances, the defense may seek exclusion of evidence where legally justified, challenge the test results through expert testimony, negotiate a reduction in charges, or argue that the prosecution cannot prove guilt beyond a reasonable doubt.
However, a DUI case does not automatically disappear merely because the blood test is questionable.
California prosecutors can also pursue DUI charges under Vehicle Code section 23152(a), which generally concerns driving while impaired by alcohol, regardless of whether the driver's BAC exceeded 0.08 percent.
Accordingly, even when the blood alcohol evidence is successfully challenged, the prosecution may attempt to rely on driving observations, field sobriety tests, officer testimony, or other evidence of impairment.
Why Hiring an Experienced Northern California DUI Defense Attorney Matters
DUI blood test cases often involve complex scientific evidence.
An attorney who understands forensic alcohol testing can investigate whether the blood sample was properly collected, transported, stored, and analyzed.
These issues are particularly important when a defendant faces serious consequences, including jail time, fines, probation, license suspension, mandatory DUI education, and a permanent criminal conviction unless post-conviction relief is obtained.
At the Davis W. Hewitt Law Office in Chico, California, we represent individuals facing DUI and other criminal charges in Butte County and throughout Northern California.
Our office understands that a laboratory report is not the end of the inquiry. When appropriate, we examine the scientific foundation of the prosecution's evidence and investigate whether mistakes in the testing process create reasonable doubt.
Contact a Chico DUI Defense Attorney
If you have been arrested for DUI in Chico, Oroville, Red Bluff, Willows, Marysville, Yuba City, or the surrounding Northern California communities, it is important to understand your legal options.
A DUI blood test may appear convincing, but its reliability depends on the procedures used to collect, preserve, and analyze the evidence.
Contact the Davis W. Hewitt Law Office in Chico to discuss your DUI case and learn whether the blood test evidence may be challenged.
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