Why did the hospital ask what state I was born in?

I just registered for a bone scan for a suspected stress fracture. I’ve registered for lots of little procedures like this in the past, tests, surgeries, etc., and never been asked this question before.

If you’re in the medical or provider business, do you know the reason? Questions about residence, citizenship status, date of birth, etc., all make sense, but state of birth? I don’t get it.

I don’t mind guesses, but if you’re just guessing, please say so. In these days of identity fraud, healthcare reform, and airport body scans, I’d like to know the actual reason.