Arizona Lawyers discusses if a Blood Alcohol Content test can be inaccurate.

DUI Defense: Can a Test of Your Blood Alcohol Content Be Inaccurate?

When a police officer pulls someone over and deems that he or she seems to be intoxicated, the results of a DUI conviction generally rest upon blood tests. Blood tests currently serve as our most adequate gauge for determining an individual’s blood alcohol concentration (BAC). 

In the state of Arizona, an individual may be charged with a DUI if their blood alcohol content tests at 0.08% or higher. These BAC tests are unfortunately one of the only forms of objective evidence that can be admitted at trial. Therefore, often the validity of these tests is a common question during the trial. 

It is important to note that an individual’s BAC level is dependent upon multiple factors such as gender, medication, and size. Furthermore, despite what has become widely accepted as a source of authority, these tests are not always conclusive. 

When your BAC is tested (either through blood or through urine), it takes anywhere from one to six weeks for the results to come back. Should your results come back as have a BAC above the legal limit, a suspension of driving privileges is then sent to the Arizona Motor Vehicle Department. After this occurs, you will receive a “Corrective Action Notice,” to make you aware that your license has been suspended. Once you have received notice from the DMV, it is important to consult with a knowledgeable and experienced DUI attorney, who can help to challenge the validity of your results. 

How Can a BAC Test Be Invalid?

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

1. Issues with the collection of blood

Often one of the issues that can invalidate a BAC test can occur when a technician is collecting your blood. Since technicians who are responsible for preparing the site and drawing the blood are often only provided minimal training, they may make a mistake that can have a serious effect. Such mistakes may include taking too big or too small of a sample, failing to properly clean the site of injection, or prepping the area with alcohol swabs.

2. Issues with the chain of custody

An extremely important component of any criminal case that involves tangible evidence is establishing a chain of custody at all times. The responsibility for proving this falls upon the prosecution. This is no different for a blood sample. The sample’s whereabouts must be known at all times from beginning to end, and whenever the sample changes hands, it must be recorded down to the time and date of the transfer. If not, it can raise questions of validity. 

3. Issues with storage

The storage of blood samples can affect the results. Blood samples are kept in vacuum-sealed tubes that contain specific chemicals to help prevent contamination and to preserve the authenticity of the sample that was taken.  Certain errors such as utilizing tubes past their date of expiration can have an effect on the results and raise into question their validity. 

4. Issues with hospital lab testing

When an individual has been involved in a severe car accident and has their BAC tested at the hospital, the results can be invalid due to the fact that the hospital labs use different techniques than forensic labs do. For example, hospitals generally only test blood plasma, which is more concentrated than testing the whole sample. Furthermore, if you have been in a serious accident, certain injuries cause lactic acid, which hospital tests generally can’t differentiate from ethyl alcohol. 

5. Issues with the laboratory and equipment

Since many forensic labs lack efficient funding, they are often understaffed and therefore equipment that is used is often not maintained, as it should be, leading to higher BAC levels. These labs are also often affiliated with law enforcement in some manner and technicians can, unfortunately, choose to taper results to help law enforcement achieve a conviction. Because of these reasons, Arizona allows DUI defendants to request a sample of the blood within 60 days of the initial testing so that they can test it at the lab of their choosing.

The Attorneys at Arizona Lawyers Help Those in Phoenix Who Have Charged with a Crime

Proving BAC testing and results to be invalid can be the difference between a conviction, affecting your life, or an acquittal. At Arizona Lawyers, we work to get you the results you deserve. To learn more or to schedule a free consultation, fill out a contact form or call us at 602-833-5376 today!

Posted in DUI