In the past, in order to get enough clotting factors, a person with hemophilia had to be injected with large amounts of the liquid part of blood (plasma).
Clotting factor concentrates have changed this by providing large amounts of clotting factor in smaller doses. Clotting factor is collected from donors or is produced in a lab (using recombinant DNA technology) and concentrated into a powder form that is then mixed with sterile water and injected.
One type of clotting factor (clotting factor VIII) is made to treat hemophilia A, and one type is made to treat hemophilia B (factor IX).