I have O- blood so had to have anti d throughout my pregnancy, So they had to get DS blood type when they did the guthrie test, Ds turned out to have A+ like DH, which was a pain as i had to have another injection!

I didn't get any documents or anything given/posted to me after, so i think they might just keep it on hospital record.

Like mumzy said in a situation where it is needed they would test themselves any way just to be certain.