How Do DUI Blood Tests Work?


Of the methods available to test a person’s alcohol concentration, blood testing utilizing gas chromatography is generally considered to be the most accurate technique. In Arizona, this is not always the case, as represented in numerous jurisdictions throughout the state. Law enforcement agencies will often conduct a blood alcohol analysis using a gas chromatograph to determine the suspect’s BAC.

Issues With DUI Blood Tests


A testing result is not the end point of your case; it is just the beginning and when the “true” DUI attorney begins to mount evidence to prepare a thorough defense. Just because a result has been rendered does not necessarily mean that it was obtained in a reliable fashion. When your blood has been tested, there are a number of standards that your DUI attorney should be investigating. Were there any problems that occurred during your blood draw? Was your blood sample properly stored? Were there any issues with the blood analysis? Who are the people in these labs running the tests? What are their qualifications? What kind of calibrators and controls does the lab use? Is the lab accredited and following internationally mandated standards? Is this “science” they use capable of producing trustworthy results? Does anyone oversee the analysts testing people’s blood?

Although it is not mandated, forensic testing labs should be accredited by a higher agency independent from law enforcement. There ought to be some mechanism in place to ensure that these testing labs are producing reliable results by using reliable methods. Reliable methods are the ones that have been approved by the scientific community, such as those established in the International Organization for Standardization’s 17025.

Your attorney should know how to review and evaluate these procedures and not merely take a lab’s stamp of accuracy at face value. If your attorney is familiar with valley and statewide lab testing procedures, generally accepted practices within the scientific community, and Quality Assurance mechanisms, he or she will be much more adept at comparing irregularities and standards.

How Mark DuBiel Uses Science in DUI Cases


Want to learn more? Click here to read about the blood testing problems at the Scottsdale Crime Laboratory.