You may not know it yet, but the State of Minnesota is one of the toughest states on drunk driving. In fact, Minnesota and only three other states allow results of urine testing to be used as evidence against people charged with DWI. This is true despite the reality that urine tests are widely known to be inaccurate indicators of whether a driver was drunk behind the wheel.
Here let's consider some of the grounds on which a urine test can be challenged in a DWI case.
First, it is important to keep in mind that police officers and lab technicians are only human and often make mistakes. Errors in the collection, handling and testing of urine samples can result in false readings and faulty evidence, and your DWI defense attorney should have the knowledge and skills to recognize erroneous results and challenge them in court.
Second, Minnesota is the only state that allows urine from the first void of the bladder to be used as evidence in DWI cases. This is important to understand because traces of alcohol can remain in your bladder long after your blood-alcohol concentration has dipped below the legal limit for drivers -- that is, 0.08.
In other words, a first-void test result could give a misleading representation of your BAC at the time you were arrested.
Third, the general assumption is that, compared to alcohol concentration in blood, the concentration is 1.33 times higher in urine. But that assumption can be very misleading, given that every person and situation is different and the ratio can actually vary by as much as two times. Tenths of a point in your BAC can matter immensely in a DWI case, so it is crucial that you have a lawyer who understands the dubious assumptions and processes of urine testing.
For more on defending against drunk driving charges in Minnesota, please see Sheridan & Dulas' Breath Testing overview. Based in Eagan, our attorneys provide full-service DWI defense.