1 as follows: whole blood from a single Group O donor was added to an ... who was found to have a positive direct Coombs test. (No prior negative reactions had been recorded.) ...

B positive, B negative, O positive, O negative, AB positive and AB negative, says the Red Cross. But of these eight, which is the most common? How often can you donate blood? And frequently ...

There are eight common blood types: A positive, A negative, B positive, B negative, O positive, O negative, AB positive and AB negative. But which is the rarest? Here's what to know.