Comment on 9,500 O-type blood donors urged to donate immediately
Zagorath@aussie.zone 2 days agoO-type is O- and O+. That’s a hyphen, not a negative sign.
O- is definitely the most valuable, since it can be given to anyone. But O+ isn’t far behind, since it can give to all the positive types, which is 86% of people, according to your source.