Blood and Urine Testing Following a Minnesota DWI Arrest

If you were unlucky enough to be pulled over on suspicion of DUI in Minnesota, chances are you will be asked to submit to a chemical test to determine your level of intoxication. These tests, which are designed to pinpoint how impaired a Minnesota driver is, involve analyzing a driver’s breath, blood or urine. Many people are familiar with Breathalyzer tests, but fewer people understand blood and urine options, which is what we’ll discuss in this article.

Blood draws

Given how important these test results can be in determining your freedom it’s important that you understand their accuracy and limitations. To start, let’s consider blood draws. Outside of extracting a driver’s brain cells and testing those for the presence of alcohol (a dangerous and surely unconstitutional proposition), blood testing is the most accurate means of determining a person’s level of alcohol concentration.

Blood draws are analyzed using a process known as gas chromatography. This is a complicated procedure that is based on the knowledge that different chemical compounds move through blood at different speeds. The test is the done by running a stream of gas through a person’s blood and comparing how the driver’s sample of blood behaves relative to other premixed samples which have been confirmed as accurate markers for various blood alcohol concentrations.

Blood tests tend to be accurate because they respond quickly to a person’s consumption of alcohol. Within minutes of a person taking a drink, the alcohol will enter his or her blood stream through the intestines. This is why a blood sample offers such a good means of measuring intoxication at the precise moment the test is taken.

However, this accuracy comes at a cost. Blood draws are also by far the most invasive means of determining a person’s alcohol content. Blood draws usually require someone with training having to stick a needle into a vein and extract the blood, far more painful and invasive than a simple breath test.

Urine tests

For the same reason that blood tests are so reliable, urine tests can be unreliable. Though alcohol is absorbed into the blood stream almost immediately, it takes substantially longer for alcohol to be metabolized by the body and appear in a person’s urine. Given this lag time, many Minnesota DWI experts believe that urine tests are actually measuring a person’s alcohol content 60 to 90 minutes earlier, a genuine problem which can result in someone being charged with DWI when the alcohol has since dissipated in their system.

Because of these troubles, many police departments in different areas of the country require that a person submitting to a urine test provide two samples. Often times a person will be required to void his or her bladder and then produce a second sample to be tested alongside the first, the idea being the second sample is more accurate given that it is guaranteed to be fresh.

Urine tests can also be skewed based on other factors that are not obvious to officers administering them. Things such as a person’s metabolism and overall level of hydration can impact the presence and extent of alcohol in his or her urine.

Find a Minneapolis DWI Lawyer

If you were recently arrested for driving under the influence of alcohol in Minnesota and submitted to a sample of your blood or urine, you should contact an attorney to discuss the reliability of these tests and the possible defenses that can be presented.  Douglas T. Kans has been litigating drunk driving related offenses and challenging chemical tests for over 19 years.  A free consultation to discuss your specific case is available, if you contact our office.