DWI Urine Tests Results: Minnesota Lab Off by 50%

Posted On July 09, 2010 by Daniel Koewler

While recently working on one of our clients DWI cases, we noticed something interesting: the client's urine sample hadn't been tested at the Minnesota Bureau of Criminal Apprehension, as is nearly every sample collected in Minnesota. Instead, the sample had been sent for analysis to the TriCounty Regional Forensics Laboratory in Anoka, Minnesota.

It didn't take long to uncover a truly massive problem - this lab wasn't reporting accurate test results. In fact, it was making huge mistakes.

As if there weren't enough problems with urine testing, we discovered another error unique to this type of test. Under Minnesota law, a driver is per se intoxicated if either their blood alcohol concentration or their urine alcohol concentration is above .08. However, whenever a urine sample is tested, the final result needs to be multiplied by .67 to take into account the fact that alcohol levels are naturally higher in urine than in blood. (Therefore, if a urine test result comes back at a .11, the forensic lab must be multiply that by .67 to get the "actual| alcohol concentration, which would actually be .07!)

When the BCA reports a urine alcohol concentration, it automatically does this routine, elementary-school math before sending its results to the prosecutor. However, in this case TriCounty Regional Forensics Laboratory forgot to perform a simple math exercise, and reported our client's alcohol concentration 50% higher than it should have been!

Because we constantly scrutinize all of the evidence that the State is bringing against our clients, we caught this error before it could permanently affect our client's rights. However, seeing this mistake on one urine test makes us wonder . . . how many other urine tests were also reported incorrectly? How many people pled guilty to DWI based on a urine test that they just |assumed| was accurate?

The lesson to be learned? Never, ever fall for the myth that the scientists working for the State are infallible. Mistakes can and do happen - more often than anyone will admit - and not catching a mistake like this can mean the difference between an acquittal and going to jail.

Update: Download the pdf of the Crime Lab's Report of Urine Test Errors