State v. Bohling
In State v. Bohling, 173 Wis. 2d 529, 494 N.W.2d 399 (1993), the Court considered whether, under certain circumstances, the fact that the percentage of alcohol in a person's bloodstream rapidly diminishes after drinking stops alone constitutes a sufficient exigency to justify a warrantless blood draw.
The circumstances the court identified were that the blood draw is taken at the law enforcement officer's direction from a person lawfully arrested for a drunk-driving-related violation or crime, and there is a clear indication that the blood draw will produce evidence of intoxication.
The Court held "that under the foregoing circumstances the dissipation of alcohol from a person's blood stream constitutes a sufficient exigency to justify a warrantless blood draw.
Consequently, a warrantless blood sample taken at the direction of a law enforcement officer is permissible under the following circumstances:
(1) the blood draw is taken to obtain evidence of intoxication from a person lawfully arrested for a drunk-driving related violation or crime;
(2) there is a clear indication that the blood draw will produce evidence of intoxication;
(3) the method used to take the blood sample is a reasonable one and performed in a reasonable manner, and (4) the arrestee presents no reasonable objection to the blood draw.
(Bohling, 173 Wis. 2d at 533-34.)