Breath & Blood Test Defenses

Many people who are facing DUI charges and agreed to take breath or blood test simply assume that these tests are accurate and that they are guilty. This is not the right attitude to take. In many cases, the breath or blood test may not have been performed properly or the equipment may not have been properly maintained resulting in an incorrect result. Fortunately, an aggressive DUI attorney will know what to look for and can expose the flaws in these testing methods.

Breath Test Defenses

Breath testing is by far the most common form of blood alcohol testing in DUI cases. However, breath testing is also the least accurate method of determining a person’s blood alcohol concentration. Currently, Colorado uses the Intoxilyzer 5000EN to perform all breath testing (however, Colorado is currently considering upgrading to the Intoxilyzer 9000). The 5000EN is an old machine and many devices in Colorado have been in use for ten years or more. As result, many of these machines routinely go in for maintenance. Fortunately, Colorado keeps records of all of the maintenance performed and a defendant was obtain these records to show that the machine has been having problems.

In addition, there are a number of other sources of error that can cause an altered result including:

  • Breathing pattern
  • Breath temperature
  • Partition Ratio
  • Mouth alcohol
  • Contaminants

In any case involving a breath test, Denver DUI attorney Jared Adams will obtain all maintenance records and solution logs for the machine used in your case. This information can often reveal that a machine has been having chronic problems. Furthermore, if necessary we will help you find the right expert to testify on your behalf to explain the true margin of error on every breath test device.

Blood Tests

Many people will opt for a blood test rather than a breath sample. In general, blood testing is considered more reliable than breath testing, but only when done properly. Unfortunately, many laboratories in the state are under funded and understaffed. As a result, numerous mistakes have been exposed in labs across the state. In 2012, it was uncovered that a laboratory technician improperly tested 1700 blood samples in DUI cases and in several cases, the results were inflated due to these mistakes. Even though blood testing is considered accurate, the tests are still performed by humans and humans can (and inevitably will) make mistakes.

In order to uncover mistakes made in a blood test, you need an attorney who understands how blood testing is performed and what to look for in order to uncover mistakes. In every blood case, Jared Adams will request what is referred to as a litigation packet. This packet will contain chromatograms that show how the test was performed and how the lab equipment was calibrated. If something went wrong with you test, these documents should expose the errors.

Furthermore, in a blood case two samples are taken and one belongs to the defendant and can be tested at an independent laboratory. If the results differ significantly, this can give rise to a challenge to original test performed by the state.


The scientific tests that are administered in breath and blood DUI cases are far from perfect. Just because you have a result that is over the legal limit you should not assume that you are guilty. An aggressive DUI lawyer will expose and uncover any mistakes that were made in your case. Call 720-333-9490 to speak with a Colorado DUI attorney and begin building your defense today.