stupid question...

this is a stupid question, but i'm pretty desperate. i'm registering for a nurse aid training program (hopefully) but i have to get the two step tb test first. i'm getting the first part tomorrow...but how long do i really have to wait to get the second one? i'm kind of in a time pinch. i've read that you have to wait 10 to 14 days but i was told by someone at the ltc that i only have to wait 7. anyone know for sure?? thanks!