Well my school did a background check with a private company, I had to give them a call and provide them my passport number (from when I entered the country) and my DL, and that was enough for them. After I graduated, I had to go through the Volunteer and Trainee services part of the hospital and they just told me that without a status (i.e. student, refugee, etc.) I wasn't allowed to volunteer there for security purposes. It didn't matter to them that I could get a background check and pass it. That's all they told me and sent me away...