"Urge to Purge": The Minnesota BCA's Attempt to use New Junk Science to Support DWI Urine Testing.

Posted On September 10, 2010 by Daniel Koewler

Urine testing has no place in determining whether or not a state's DWI laws have been violated. Despite near universal rejection of urine specimens for DWI enforcement, the folks at the Minnesota Bureau of Criminal Apprehension (BCA) stand nearly alone in continuing to use this junk science to put people behind bars.

Our firm has been at the forefront of the fight against urine tests, demonstrating again and again exactly why urine testing has no place when it comes to enforcing DWI laws. In every case we present decades of scholarly articles and learned treatises rejecting urine testing.

Because of our success, the BCA has come up with some new "evidence| in an effort to build support for DWI urine testing in Minnesota. Last week the state presented a single piece of paper drafted by one BCA scientist that we've lovingly dubbed the |Urge to Purge| memorandum. This memorandum attempts to overcome the obvious fact that when you are given a urine test, the sample demonstrates a |pooled| or average alcohol concentration, and not your actual alcohol concentration from the time you were driving. Basically, a urine test can report â?? at best â?? an average alcohol concentration since the subject had last voided his or her bladder.

The |Urge to Purge| memorandum tries to imply that the diuretic effect of alcohol (the well-known fact that drinking makes you have to pee) means that anyone who is drinking is also peeing non-stop, and so any urine sample will be |accurate enough.| What the data doesn't take into account is simple science; specifically, the well-documented fact that the alcohol only has a diuretic effect during the absorptive phase of alcohol (which stops about an hour after drinking) and not during the post-adsorptive phase (after the alcohol has been fully absorbed).

It appears the state seeks to use their new |science| to refute the well-founded legal position that the police need a search warrant to force a urine test. Because alcohol doesn't dissipate in the bladder, there is no immediate need to obtain a sample, as in the case of breath tests. The state's |urge to purge| memorandum implies that a person will wet their pants before a cop can get a warrant. There is no science to back up the state's claim.

To make a long-story short, the |Urge to Purge| memorandum that the BCA is now touting is about as relevant to urine testing as a chart explaining how blondes have more fun. It just doesn't matter.

Hopefully - someday - the BCA will learn not to support junk science with more junk science. Until that day comes, we'll be here, continuing to attack this flawed test in the courtroom.