The Arizona Court of Appeals has ruled state prosecutors can't use the results of warrantless blood-alcohol tests as evidence against people who are threatened with arrest when they refuse to go to a hospital. 

The case comes out of Yavapai County — a woman drove off the roadway and hit a guardrail. Another driver took Vi Ann Spencer to a fire station, where she refused to go to the hospital. A law enforcement officer eventually told Spencer if she didn’t go to the hospital, he’d arrest her. She decided to go to the hospital, and a blood-alcohol test done there showed her level was higher than the legal limit.

The appeals court decision overturns Spencer’s convictions, and orders that she be given a new trial. Thursday’s ruling says the test results couldn't be used as evidence because there was no warrant and because Spencer didn't voluntarily consent to the treatment that led to the blood draw. The judges write that nothing suggests Spencer was ever advised she had the option of going home, if someone else drove her.