In a nutshell, yes they can, if they have probable cause to arrest you for a DUI. In general there are a couple of ways you can wind up having your blood drawn during a DUI arrest.
First, under the NC implied consent statute you give consent for an officer to test you by breath, blood, or urine if charged with an implied consent offense (driving under the influence of an impairing substance). You can refuse to take the tests, but if you do you are subject to an automatic 1-year revocation of driving privileges by the DMV.
Once you refuse, the officer still may draw your blood with a search warrant. To get the search warrant the officer has to fill out a warrant request form. Then warrant then has to be signed by a magistrate. Many counties in NC have a magistrate on duty 24 hours a day. If the magistrate is not available or the officer believes that getting a warrant will cause a substantial delay leading to the dissipation of alcohol in the blood stream, then the officer may be able to avoid the warrant requirement by arguing that exigent circumstances existed.
Alcohol will only stay in the blood temporarily, which makes time of the essence to collect and subsequently use your blood as evidence against you. If the officer reasonably believes there will be a substantial delay in getting the search warrant due to the unavailability of the magistrate, distance to the hospital, crime scene collection, traffic etc., then the officer may attempt to collect blood against your will and without a warrant. Whether the resulting blood draw would be allowed into evidence is something that could be addressed in front of the presiding judge at court.
The prevailing case law in North Carolina for a warrantless blood draw was based on the officer’s experience that the Magistrate’s Office was 12 miles away and particularly busy on a Saturday night, and the hospital was also very busy on a Saturday night. The officer estimated the delay at 2-3 hours and decided to go straight to the hospital for the blood draw. The Court of Appeals found the officer’s reasoning acceptable and allowed the blood result into evidence.
Missouri v. McNeely
The United States Supreme Court decided in the landmark DWI case of Missouri v. McNeely, that dissipation of alcohol from the bloodstream does not by itself constitute exigent circumstances that would allow a warrantless search.
In North Carolina, Gen. Stat. 20-16.2(b) allows an officer to draw the blood of an unconscious person without a warrant so long as the officer believes the person has committed an implied consent offense. This blanket exception to the warrant requirement appears to contradict the U.S. Supreme Court’s ruling in McNeely and may create a legal argument that 20-16.2(b) is unconstitutional.