Two plus two equals...?

Lab technicians in a crime law servicing three Minnesota counties couldn't figure out how to calculate alcohol concentrations in urine tests, leading to test results in 111 cases that overstated alcohol concentrations by 50%. In Minnesota a breath test is included in field sobriety testing. A urine test is then conducted at the station as "confirmation" of the alcohol concentration.

The only problem was lab techs failed to multiply the urine test result by .67 which led to inflated test scores. In Minnesota, as with most states, alcohol concentration is calculated based on grams per 210 liters (g/210L) of breath, grams per 100 milligrams (g/100mL) of blood and grams per 67 milliliters (g/67mL) of urine.

In a number of cases, even when calculated correctly, the alcohol concentration still exceeded the legal limit permissible. However, since penalties for DWI in Minnesota are determined, in part, by the alcohol concentration of the driver, some motorists accepted pleas for penalties more severe than might otherwise have been offered.

"It just goes to prove there is error. Science isn't always reliable when it's conducted by people. We see other cases where juries base decisions heavily on scientific evidence." -- Virginia Murphrey, Interim Chief Public Defendant, Anoka County, MN

Interestingly enough, the police may request either a blood or urine sample to "confirm" the breath test result -- but in these cases the police chose the least reliable test possible.