Clotting factors are substances in the blood that help stop bleeding when a blood vessel is damaged. People who have clotting disorders, such as hemophilia, have clotting factors that do not function properly.

When the blood doesn't clot normally, even minor injuries can cause serious bleeding. This can lead to blood loss, injury to internal organs, or permanent damage to muscles or joints.

Most people who have clotting disorders can successfully manage their bleeding problems with clotting factor replacement therapy. Clotting factors may be injected on a regular basis to prevent bleeding episodes, or on an as-needed basis to prevent or control a bleeding episode that has occurred or is likely to occur.