In State v. Tanksley, the Minnesota Supreme Court recently affirmed DWI urine testing procedures despite concerns that the urine testing does not accurately reflect a person’s blood alcohol content. Although the source code challenge has taken most of the spotlight, Minnesota DWI defense attorneys have been bringing challenges on another front as well: first-void urine testing. The ruling by the Supreme Court likely closes any further judicial challenges to the regime, but suggests that the road ahead may lie with the legislature.
So, what’s the fuss about? Minnesota provides for three tests to determine if a driver is over the legal alcohol limit: blood, breath, and urine. The issue in Tanksley was whether first-void urine testing was reliable scientific evidence. First-void urine is the initial urination after it has pooled in the bladder for a while. The trouble with first-void urine is that alcohol can build up in the bladder even after it dissipates from the blood stream. So, a first-void urine test could result in an alcohol concentration higher than the driver’s actual blood alcohol content if they had not urinated recently before.
Despite the concern over first-void urine’s reliability, the Supreme Court noted that the DWI statute defines alcohol concentration as “the number of grams of alcohol per 67 milliliters of urine.” Because the statute doesn’t require the test to correlate to a person’s actual blood alcohol content, first-void urine was held to be admissible.
So, we’re left with a situation where reliability concerns over first-void urine testing still exist, but the statute allows the evidence in with indifference. Since the State is concerned with punishing those who are intoxicated — not those who merely have a large amount of alcohol left in their bladder — we’ll see if a legislative fix will be forthcoming.