Blood Tests

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  8. Driving Under the Influence Per Se (“DUI Per Se”)
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  15. Standardized Field Sobriety Tests (SFSTs)
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Although the blood draw is done by a local medical professional, after the blood is collected, it is usually placed into evidence and then delivered by law-enforcement courier to the Colorado Bureau of Investigation (CBI) for testing. CBI’s forensic toxicology department will test the blood in accordance with the law and established lab procedures. This process, unlike with breath testing, takes several weeks. Also unlike breath testing, which in Colorado is presently limited to detecting alcohol, blood testing can test for the presence of drugs other than alcohol.

This is an example of the blood testing results from a private laboratory:

Private Lab Blood Test Result

For more information about blood testing, visit CBI’s Forensic Toxicology webpage. This website offers:

        1. Contact information for testing,
        2. Access to testing kits,
        3. Information about the lab’s accreditation,
        4. Drug effect monographs, which outlines a CBI forensic toxicologists general testimony about the potential effects of various drugs,
        5. A list of current forensic toxicologists and their Curriculum Vitae’s, and
        6. Information on how to order Expert Disclosure Reports and BAC “Retrograde Extrapolation Reports.”

Retrograde Extrapolation Reports

Alcohol takes time to metabolize in the body, and the BAC at the time of testing may differ from the BAC at the time of driving.

Retrograde Extrapolation Graph

Retrograde extrapolation reports can be used to help determine a person’s BAC at the time of driving. You will want to obtain one of these reports in a variety of circumstances, such as if a person’s BAC at the time of testing was under the “Legal Limit,” but the evidence at the time of driving demonstrates the defendant was under the influence. A retrograde extrapolation can also estimate a defendant’s BAC for purposes of proving DUI Per Se.

CBI Litigation Packet

When requested, CBI will also provide to the prosecution what is known as the “CBI Litigation Packet,” or “lit packet” for short. This packet documents chain of custody on evidence, all testing, and all results. CBI does not provide this to defense counsel. Nor does CBI automatically provide it to the prosecution. You should order it in anticipation of trial and provide it to the defense. Your legal assistant will know how to order a lit packet.

Resources

CDAC Videos

Marijuana Toxicology 101

Toxicology in Drug-Impaired Driving Cases—Part 1

Toxicology in Drug-Impaired Driving Cases—Part 2

Widmark Calculations and BAC Extrapolation

Forensic Toxicology

Blood Alcohol Pharmacokinetics and Retrograde Extrapolation

Colorado Resources

CBI Forensic Toxicology Testing

National Resources

Alcohol Toxicology for Prosecutors

Drug Toxicology for Prosecutors