Are Blood Tests Reliable?

“Is it better to take a breath or blood test after a DUI arrest?” As a DUI defense firm, we get this question a lot and not just from clients. DUI attorneys generally suggest staying away from blood tests since they can present more difficulties when fighting in a court than a breath test. In other words, they’re harder to challenge than breath tests, but that doesn’t mean they’re infallible.

In regards to breathalyzers, there are a variety of factors that could result in a false reading in a breath test, such as the presence of mouth alcohol, the rising alcohol level, diabetes, ketosis, and even the presence of acid reflux. In the mind of the jury, a blood test is a solid indicator of blood alcohol concentration (BAC) levels. So, how can you disprove blood evidence in a DUI case?


While blood tests are considered the more concrete test, there are results that can be inaccurate or tampered with, whether intentional or not. If you have been involved in a DUI arrest and have had a blood sample taken, don't despair. An experienced DUI defense lawyer from the Law of Virginia L. Landry, Inc. can defend you from the results of your blood test results.

Ways to challenge blood test evidence:

  • Get the blood sample tested at an independent laboratory to search for errors.
  • Prove contamination of the blood after it had been collected.
  • Show that blood samples have been switched or intermingled with other samples.
  • Explain how fermentation of the blood sample has caused it to produce its own alcohol.

Since blood tests may not provide an accurate reading of a suspect’s BAC, California law has mandated protocols. Some of these rules include obtaining the blood sample in a hospital-like environment using acceptable medical tools, using proper storage procedures for the sample, and accounting for anyone that may have had access to the sample.

If these rules are not followed, your lawyer can argue that the breach in protocol was a violation of your rights and that the results of the blood test should be inadmissible in court. If evidence is suppressed in a DUI case, it can lead to a dismissal in charges.

Related: DUI Truths People Don’t Know

If you’ve been arrested for DUI and have had your blood taken for BAC testing, remember human error is more common than you may think. Working with our firm can prove fundamental problems with the test results made by human error, which may ultimately result in reduced or eliminated charges. Contact us to get started!

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