Following a person’s arrest for a DUI/DWI criminal offense, police officers will ask the accused/defendant to submit to a blood test or blood draw in which a qualified person such as a nurse at the police station or hospital will draw the defendant’s blood (usually from the arm) into a vial to be tested for alcohol concentration and ultimately to determine whether the person is per se intoxicated. Per se intoxication is intoxication by definition—as defined in the state’s statutes, which is often a blood alcohol concentration (BAC) of .08 or higher.

All states have implied consent laws that make a driver’s consent or agreement to submit to a blood, breath, or urine test (a chemical test) when requested by a law enforcement officer a condition of the driver’s acceptance of a driver’s license offered by the state. Despite implied consent laws, in 2013 the United States Supreme Court held that if a person refuses to submit to having their blood drawn the police cannot draw the blood by force without a search warrant, as required under the Fourth Amendment to the United States Constitution. But more recently the Supreme Court upheld a nonconsensual blood draw of an unconscious person suspected of driving under the influence—based on the state’s implied consent laws and the exigent circumstances exception to the Fourth Amendment's warrant requirement.

And if a driver refuses to take a blood or breath test there are other consequences even if the police do not secure a search warrant for the blood draw—including admission of the refusal in evidence at trial, fines, penalties, and automatic suspension of the driver’s license for a year or more.

In Arizona, following a DUI/DWI arrest, police officers may request the accused to submit to a blood test to determine their blood alcohol concentration (BAC). Arizona law considers a BAC of 0.08 or higher as per se intoxication. Under Arizona's implied consent laws, drivers have implicitly agreed to submit to chemical tests (blood, breath, or urine) as a condition of holding a driver's license. Refusal to submit to such tests can lead to evidence of refusal being admitted in court, fines, penalties, and an automatic suspension of the driver's license, typically for 12 months for a first offense and 24 months for subsequent refusals. Following the 2013 U.S. Supreme Court ruling, police cannot forcibly draw blood without a warrant unless exigent circumstances exist. However, in cases where a suspect is unconscious, the Supreme Court has upheld nonconsensual blood draws based on implied consent laws and exigent circumstances. It's important for individuals in Arizona to be aware of these laws and the potential consequences of refusing a chemical test after a DUI/DWI arrest.