How Accurate are Blood Tests… really?

don't drink and driveAccuracy Of DUI Blood Tests

When you’re pulled over for suspicion of drunk driving, officers can use different means of testing to determine if you should be charged with DUI including field sobriety testing, breathalyzer, urine, and blood tests.  While roadside breathalyzers are the most common and easily accessible means of testing, they are prone to miscalibration, human error and all manner of interferences. Field sobriety testing is open to the interpretations of the arresting officer and can be negatively impacted by issues with age, weight, medical and weather conditions. Urine testing, while less invasive than blood testing, needs to be correlated correctly in order to show accurate results.  And, although Blood tests are considered to be one of the most accurate forms of chemical testing when it comes to determining a person’s blood alcohol content (BAC), they are prone to errors as well.

Here are some of the shortcomings to blood testing.

  • Cross Contamination- One of the biggest causes of fluctuation in the results is due to cross contamination. Unfortunately, it’s the measure that is meant to protect you that can be what condemns you. The alcohol swab used to clean the area before the sample is taken can cause a spike in the BAC results of the blood test.
  • Mishandling the Sample- Mishandling the sample can cause several issues with the result of the test. Letting it sit too long or improper storage can cause the blood sample to break down which can affect the results of the blood test.
  • The amount of time passed between being stopped and being tested- Depending on how long it takes to get you to the police station or the nearest hospital can have an effect on the test results. This can show a lower level of BAC from what it was when you were actually pulled over.
  • Diabetics, Cough Syrup, Herbal Medicine- Most cough syrups as well as herbal medicines contain a fairly high measure of alcohol. While it’s not enough to get you drunk, it is enough to tip the scales of a blood test. Diabetics are even more susceptible to erroneous results due to having a higher ketone level in their blood which results in a higher BAC reading.

Blood testing is often considered to be the most reliable form of chemical testing and can be the hardest to refute.  The results of your blood test can provide the prosecution with evidence to use against you in Court that may lead to a DUI conviction. If you find yourself in this situation, then you’re going to need the help of an experienced DUI attorney with a proven track record of successfully disputing the results of blood testing.  Remember, a DUI conviction will stick with you for the rest of your life and it doesn’t just affect you, but your family and your livelihood as well.  Contact the law offices of Alpert Schreyer and get a free consultation from an experienced DUI attorney.

About Andrew Alpert

+Andrew is one of the leading DUI and criminal defense attorneys in both the state of Maryland and the District of Columbia. He blogs about Maryland DUI law, has numerous videos on the subject and has been asked to appear on national television to offer his legal opinion on high-profile criminal cases.