If you are pulled over on a Georgia roadway and are under suspicion of driving under the influence (DUI), chances are that you may be tested for the total level of alcohol in your blood. One common way to do this is through a blood alcohol test.

The blood alcohol test is inaccurate in many cases, and is often challenged in court. An Alpharetta DUI lawyer explains the test and its reliability.


How Does Alcohol Get Into Your Blood?

Alcohol, also known as ethanol, is absorbed into your bloodstream when you drink an alcoholic beverage. About an hour after taking a drink, it reaches its highest level. It may take longer to peak in your blood if you have recently eaten a meal.

Once in your system, larger amounts of alcohol can depress your central nervous system and sedate you. Even smaller amounts can have noticeable effects.


What is Blood Alcohol Content?

Your blood alcohol content (BAC) is a number that represents the percentage of alcohol in your blood. Simply put, the more you drink, the higher your BAC. In Georgia, adults are considered legally intoxicated if their BAC is .08% or higher. For those under age 21, the number is lower, at .02%. For commercial drivers it is .04%.


What is a Blood Alcohol Test?

If you are given a blood alcohol test to determine if your BAC is at or above the legal limit, you will have blood drawn from your arm. You can expect the following:

  • An elastic band will be placed around your upper arm to stop the blood from flowing.
  • The area will be cleaned, a needle will be inserted into your vein, and blood will be collected in a tube. Afterwards, the band will be removed and the needle site cleaned and bandaged.
  • The tube of blood is tested in a laboratory to determine your BAC.


Why Are Blood Alcohol Tests Sometimes Unreliable?

There are many factors that can lead to unreliable blood alcohol test results. Some of the more common are:

  • Medications—prescription and non-prescription—can influence the test outcome. In fact, some over-the-counter cough medications can skew the results. Anyone testing your blood should know what prescriptions you take.
  • Accuracy of blood alcohol testing can vary greatly depending on the lab doing the testing. Law enforcement labs may not be nearly as accurate as a hospital lab because their procedures may vary.
  • False high readings can occur if the blood sample sits around for a long time before being tested. Blood that coagulates or decomposes often reads much higher.
  • People with diabetes or who have high blood ketones are subject to inaccurate blood test results.


It is important to understand that blood alcohol testing is still the most reliable way to determine whether a person is intoxicated. Courts do tend to trust the results—especially if the BAC is above .08%. However, time after time, DUI cases are successfully challenged by questioning these results.

If you have been arrested for DUI, you should consult an Alpharetta DUI attorney with your questions and concerns. The Law Office of Scott Miller offers a free initial consultation, so call the office at 770-408-1001 or fill out the contact form on this page today.

Scott Miller
Connect with me
Georgia Attorney at Law

Get Help Now

Fill out this short form and Criminal Defense Lawyer Scott Miller contact you quickly about your traffic, DUI, misdemeanor, felony or probation violation case.