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 popular technique. In Arizona, this is not always the case, as represented in numerous jurisdictions throughout the state who use breath testing, which is used on a device commonly referred to as an Intoxilyzer. Blood testing is a separation science run on a Gas Chromatograph (“GC”), but before the test is ever run, there are many steps that the state’s lab worker must take, all of which must be followed to a “t” to ensure your results are both accurate and reliable.

In general, the blood vial to be tested must come from the evidence locker (and should have been inspected and accounted for every step along the way). There have been recent instances of test tubes not containing the preservative and anti-coagulant, which compromises the quality control of the testing process. Next, once obtained, the lab worker must take inventory of the contents of the blood kit, as well as each and every other blood kit taken for that day’s testing run. The analyst then has lots of prep work, (such as labeling vials, rocking samples to ensure homogeneity, pipetting blood into the testing vial, and observing the samples as they are run, etc.), for every blood vial, every calibrator sample, and every control sample before any of the science happens on the GC. It is imperative that the lab technician takes note of every step accurately. Every step must be done meticulously, using scientifically recognized methods, equipment, and materials. The GC must be working properly and accurately as well. Finally, all of the controls and calibrators must meet national and international standards in order to claim there is a valid run. Far too often, labs will cut corners when it comes to this crucial step. Over the years, there have been many cases valley wide in which these steps have been done incorrectly, fallen below standards, and resulted in a compromised blood testing run, leading to unreliable test results.

Issues With DUI Blood Tests


A testing “result” is not the end point of your case; it is just the beginning, when the “true” DUI attorney begins to prepare a thorough defense involving the science used to convict many arrestees. 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 inspection when the vials were removed from evidence? Were there any issues with the toxicology notes on your client’s blood vial? Who were the techs in the lab running the tests? Are they properly qualified? Does the lab use and maintain scientifically accepted calibrators and controls? Is the lab accredited? Does the lab follow international minimum standards required of labs reporting measurable results? Are the method, quality control, quality assurance, and personnel capable of producing trustworthy results?

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. There are a plethora of instances valley and state wide that show these labs cutting corners with hardware, software, and quality control, all compromising the reliability of the end result.

At the Law Offices of Mark D. DuBiel, we know how to review and evaluate these procedures and not merely take a lab’s stamp of accuracy at face value. Further, we work with multiple local and national issues as needed to defend DUI charges involving a blood DUI. In fact, not only have we lectured to local and national practitioners on these issues, but we have also published several legal treatises that are relevant to the blood testing process as well as involving expert witness in the process. It is imperative that your attorney is very experienced with the forensic side of DUI charges, and we at the Law Offices of Mark DuBiel are intimately familiar with valley and statewide lab testing procedures, generally accepted practices within the scientific community, and quality assurance mechanisms, all of which make us more adept at comparing irregularities and standards, ultimately giving you the best chance to beat your DUI charges.


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.