Why is blood needed from diverse donors?

We need blood from diverse donors because a diverse group of patients will receive it. People with sickle cell disease or thalassemia can be any race or ethnicity, but almost all have ancestry from the parts of the world shown on the map below.
Since we all inherit our blood type from our parents, transfused blood is most likely to be a close match when the donor and the patient have similar ancestry. Donations from people with relatives or ancestors from the parts of the world shown in the map are key to the health and safety of those with sickle cell disease or thalassemia who need transfusions.
Many people who have sickle cell disease or thalassemia get blood transfusions to stay healthy. They may need them regularly their whole life, or for certain short periods of time, or off and on during health emergencies.
If someone gets transfused with blood that doesn’t quite match their own, their body can create antibodies to fight it off. This is not usually dangerous on the first exposure. But if that patient gets blood later with the same mismatch — even years later — their body can create a flood of antibodies trying to destroy the donor blood. This is very serious, even deadly.
So people who might get many transfusions in their lifetime — like people who have sickle cell or thalassemia — need to get donor blood that is a close match to their own every time. If they already have an antibody, they definitely need to avoid getting donor blood with the same mismatch.