If you're positive for RH, you'll react with somebody that isn't. Without an RH, it doesn't matter. But if you were to give blood to somebody that's B-, it would react and coagulate which wouldn't be good. Whereas I am negative for RH, so it doesn't affect the other person.
I don't know mine but I'm going into the hospital for an appointment next month. I'm going to ask them then since they should have it on file. My mom and brother are both AB positive.