Not adding much to the other responses - yes, those other blood groups matter, that's how they found them. The majority of the population does not have antibod

Not adding much to the other responses - yes, those other blood groups matter, that's how they found them. The majority of the population does not have antibodies to the other blood groups - the majority of the population is covered with the basic 4. Blood group conversion (A, B, and AB to O) would be fantastic - it doesn't solve all the problems. As stated elsewhere - please donate blood! A lot of the interesting things we do in medicine are predicated on blood availability: trauma, many obstetrics cases, cancer treatment, organ transplant (including bone marrow transplant), major surgeries, etc. If you can't donate, encourage others to do so!