After you’re pulled over, an officer will conduct field sobriety tests. If a drug recognition expert is there, that officer will test for signs of drug impairment, such as dilated or pinpoint pupils.
You’re then handcuffed and taken to jail. The arresting officers will check your record for past DUI convictions. After your belongings are taken and you have been searched, your vitals will be checked at the jail. A phlebotomist will then take your blood for testing.
If you refuse the blood test, or if you were involved in a crash resulting in significant injuries or death, officers will contact the on-call judge to get a search warrant. If the search warrant is approved and you still refuse, officers will forcibly take your blood.
The blood tests are more accurate when taken within two hours of the arrest. If it’s past two hours, your blood will be drawn twice for more accurate testing. If you have had two prior DUI convictions, you will be charged with a felony.
If you’ve caused a crash that resulted in significant injuries or death, that also will result in a felony charge.
via Las Vegas Review Journal