Question

Which blood part does a hemophiliac must receive a regular injections to stay alive?

Answer 1

I believe it's plasma. Because hemophiliacs lack the plasma for their blood to clot.

Yes it is plasma:
"Hemophilia C. The clotting factor missing in this type of hemophilia (factor XI) is available only in Europe. In the U.S., plasma infusions are needed to stop bleeding episodes."
http://www.cnn.com/HEALTH/library/hemophilia/DS00218.html

Although that's to stop bleeds, it reads like they get injections of a clotting agent hormone thing regularly as a normal treatment, but that's not really a part of the blood.

Answer 2

thanks