Criminal Defense Lawyer Serving Ann Arbor

Lab Errors can Plague DWI Tests

Popular culture tends to frequently dramatize field sobriety testing. Popular characters on television, in movies and in books are asked (with surprising regularity) to recite the alphabet backwards and to walk a straight line while touching their nose with alternating pointer finger. Field sobriety testing is utilized by some law enforcement agents during drunk driving stops. However, breath and blood alcohol testing is utilized far more frequently.

One of the primary reasons why blood and breath testing is used so often is that it is considered a more reliable indicator of someone's level of intoxication. In fact, many people believe that lab testing is the ultimate answer to the question of someone's blood alcohol concentration; however, this isn't always the case. 

The Breathalyzer

Many people are familiar with the breathalyzer. For those who might not know, the breathalyzer is a blood alcohol concentration test that measures the amount of alcohol in someone's breath. It uses the concentration of the alcohol in the breath as a surrogate for the amount of alcohol in their blood; however, there are several ways that this test could produce inaccurate results.

First, the breathalyzer must be properly calibrated. The machine is comparing the alcohol in someone's breath to a known standard. If the standard is inaccurate, then all measurements taken against this standard are also inaccurate. Furthermore, there are certain substances in someone's breath that can potentially throw off the test results. It is important that people speak with a legal counsel to learn more about the issues with a breathalyzer.

The Blood Sample

This is supposed to be the gold standard when it comes to measuring blood alcohol concentration. The legal limit for BAC in the United States is 0.08. Any amount over the limit constitutes a DWI. Measuring the blood directly should produce the most accurate results; however, there are issues with this test as well. For example, some medical personnel will draw the blood sample and let it sit for an extended period of time. Over time, the blood sample will clot, leading to issues determining an accurate reading.

Furthermore, some people may have congenital blood disorders that make it challenging to read the blood sample accurately. Finally, there is always the question of when the blood sample was drawn. Did the person have their blood taken hours after the arrest was made? If this is the case, the blood sample drawn may not accurately reflect the alcohol level at the time the arrest was made.

In the end, these are only a few of the ways that lab errors can lead to faulty test results. This is important because the accuracy of the results is going to carry a significant amount of weight in a court of law. When someone is charged with a DWI or OWI, they are entitled to the strongest defense possible. Anyone who is facing a possible conviction for driving under the influence should consider hiring an experienced criminal defense attorney in order to better ensure that kind of strong legal defense.