DUI Blood Tests – Whole Blood vs. Serum Testing

Driving under the influence of drugs or alcohol has been proven to impair decision-making, slow reaction times, and increase the risk of an auto accident. With all the risks associated with DUI, it is understandable that this crime carries harsh penalties. Unfortunately, some drivers are unjustly prosecuted or given overly strict sentences, largely due to inaccurate chemical testing. Those who have been arrested for DUI should contact an experienced DUI defense attorney, such as James Novak, to ensure their rights are protected throughout the criminal proceedings.

A DUI blood test measures the concentration of alcohol in the blood to show how inebriated the subject is at the time of arrest. Chemical BAC tests are often the strongest piece of evidence in a DUI case. Blood tests are known to be the most accurate form of DUI testing. However, errors or inaccurate readings can occur. Here, we compare the two techniques for DUI blood tests – whole blood vs. serum testing, and discuss how our Phoenix, AZ clients’ results may be affected by the type of testing that was used during their arrest.

Whole Blood Testing

When a DUI blood test is performed, a small sample of blood will be drawn for testing. After the blood is removed, it will be tested to determine the concentration of alcohol that is present. Whole blood testing is the most accurate form of DUI blood testing. The whole blood contains cellular material, plasma, and a clotting agent called fibrinogen. This solution should be tested in its entirety to get a true measure of alcohol in the blood. Whole blood testing is known as the forensic form of blood testing, because it is concerned with the precise concentration of alcohol.

Serum Testing

When DUI blood testing is performed using a medical blood draw, it is likely that only the serum of the blood will be tested for alcohol. During this testing procedure, the blood is processed in a centrifuge. The centrifuge cleans the blood to remove any solid, cellular material, leaving just the “serum.”

The problem with serum testing is that it leaves the same amount of alcohol in a significantly smaller sample of blood. Serum testing can determine whether alcohol is present in the blood, but it does not provide a precise measure of blood alcohol concentration. In fact, studies have shown that, on average, serum testing results in blood alcohol content results that are about 16 percent higher than those of whole blood testing.

The Problem with Serum Testing

The inaccuracy of serum testing is a huge problem in DUI cases. In most states, a DUI arrest is based on blood alcohol content, with .08 being the average level at which a person is considered legally intoxicated. However, the issues with serum testing go beyond this.

Most states also penalize DUI drivers based on their BAC, with higher levels of BAC being subject to harsher criminal penalties. If there is no accurate measure of blood alcohol content, that is a great source of contention in a DUI defense case. Attorney James Novak understands the inaccuracies of serum testing and will use this defense strategy, when applicable, to protect the rights of his clients.

Contact Us

If you’ve been arrested for DUI, it is important to have an experienced attorney on your side that understands the intricacies of DUI criminal charges. Attorney James Novak has the experience and expertise to provide you with a strong DUI defense. Contact us at your earliest convenience to discuss the details of your case and find out how we can help you avoid serious criminal penalties.