17-year-old Isaac Cardenas got away from officers Thursday afternoon while at Community Regional Medical Center.
Officials say he was getting medical clearance before he could be booked into the juvenile justice campus.
He's 5'9" with brown hair and brown eyes.
Cardenas was last seen wearing a black T-shirt and beige sweat pants.
Authorities say he has a history of violent crimes and is considered dangerous.
If you see him, call 911.