The Phoenix DUI Law Blog

Challenging DUI Blood Test Results: It Can Be Done

Challenging a DUI blood test may sound like an impossible task. But there are several ways to do it if you think the results are unfair.

That doesn't mean the challenge will always be successful. But a test that shows your blood alcohol level was over the legal limit -- 0.08% for adults 21 and over in Arizona -- isn't necessarily a guarantee that you'll lose in court.

Mistakes happen with blood tests; the technicians are only human. To take advantage of that, you just need to know where mistakes are most likely to happen. Some examples of potential mistakes include:

  • The person taking your blood. Not just anyone can open up your veins to get a sample. Courts require that the person who draws the blood be qualified to do so, which often disqualifies police officers. If your blood wasn't drawn by a medical professional, it might not be reliable enough for the court. Not to mention that there can be reliability issues -- if the technician was fabricating results, for example.

  • The chain of custody. To ensure that a blood sample wasn't tampered with, courts require that there be a clear chain of custody. Authorities must provide a list of everyone who handled the sample between drawing the blood and testing it. Any gaps in the chain could weaken the evidence and lead to its exclusion at trial.

  • The equipment. People can make mistakes, but machines can mess up too if they haven't been calibrated correctly. It's not just Breathalyzers that can be challenged for potentially mistaken results. Blood test evidence could be thrown out if the equipment wasn't properly maintained.

But just because you can challenge DUI blood test results doesn't mean you should. How can you tell if it's the right choice for your case? You might not know, but an experienced Phoenix DUI lawyer will.

That same lawyer may also be able to find unique blood test challenges that are specific to your case. No matter what, it's better than going it alone.

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