Ceja Law Firm, PLLC discusses the ways a blood alcohol content test can be inaccurate.

DUI Defense: Inaccurate Blood Alcohol Content Test

When you are pulled over and suspected of being under the influence, you will likely be given a blood test in order to determine your blood alcohol concentration (BAC), which is also known as the blood alcohol content test. In the state of Texas, an individual must be at least 21 years of age in order to legally consume an alcoholic beverage. 

It is illegal to drive under the influence of alcohol. One is considered under the influence if they have a BAC of 0.08% or higher and they will be charged with a DUI. For those under the age of 21, a driver must not test positive for any BAC – even if that amount is under the legal limit of 0.08%. Should this be the case, you may be charged with a DWI. Unfortunately, there are very few forms of objective evidence able to be admitted in a DUI or DWI trial. Because of this, these tests are commonly used as evidence, leaving the defendant to question their validity as a defense. 

It should be known that despite their pervasiveness, these tests are not always conclusive. An individual’s BAC results from numerous factors including gender, size, and medication. 

Invalidating a BAC Test

There are five different ways in which the blood alcohol content test can be invalidated. These include the following:

1. Blood Collection Issues

Technicians, who are responsible for prepping the site and drawing the blood are commonly provided minimal training and may, therefore, make a mistake that can have a serious effect. These mistakes include taking too big or too small of a sample, failing to properly clean the site of injection, and failing to prep the area with alcohol swabs.

2. Chain of Custody Issues

Any criminal case that involves tangible evidence must establish and always maintain a chain of custody. The prosecution has the burden of proof. The whereabouts of a blood sample must be known at all times, including whenever the sample changes hands. When this occurs it must be recorded down to the time and date of the transfer.

3. Storage Issues

How blood samples are stored can have an effect on the results. Blood samples are kept in vacuum-sealed tubes containing certain chemicals that help to prevent contamination as well as preserve the authenticity of the sample.  Mistakes such as using tubes past their expiration date can have an effect on the results.

4. Hospital Lab Testing Issues

Hospital labs utilize different techniques from forensic labs. Hospitals generally only test blood plasma, which is more concentrated than testing the whole sample. Additionally, certain injuries may cause lactic acid, which hospital tests generally are unable to distinguish from ethyl alcohol. 

5. Lab and Equipment Issues

Forensic labs commonly lack funding and enough staff. Therefore it is not surprising that equipment is often not maintained, which can result in an inaccurate reading and perhaps even a higher BAC. Additionally, since these labs are often related to law enforcement, technicians sometimes choose to shape results to help them achieve a conviction. 

The Attorneys at Ceja Law Firm Help Those in Houston Who Have Been Charged with a DUI

Once you have been charged with driving under the influence, it is important to consult with a knowledgeable and experienced DUI attorney, who can help to challenge the validity of your results. 

Invalidating a BAC test can be the difference between a conviction and an acquittal. At Ceja Law Firm PLLC, we will work to help you obtain the best possible outcome. To learn more or to schedule a free consultation, fill out a contact form or call us at 713-987-3425 today!