The man from Vännas, near Umeå in northern Sweden, confessed to driving over the legal limit.
The man was requested to take a blood test and, as is standard medical procedure, a nurse used a packaged wet towel to clean and disinfect the area beforehand.
The towel contained alcohol which was evidence enough for a district court in Umeå to acquit him on all charges.
The case was thrown out because the test, which revealed he had a blood-alcohol content level of over 1,5 milimetres, could not be deemed valid due to the element of alcohol in the towel which could have affected the result.
In the appeal court hearing prosecutor Inga-Lis Adervall-Åström brought in a medical expert who confirmed there is little or no risk that a blood test can be affected by cleaning the area beforehand.
The man was found guilty and sentenced 50 hours of community service.