Blood Home > Hemophilia B
The major signs and symptoms of hemophilia B are bleeding and bruising. Bleeding often occurs internally, such as in joints and muscles. If bleeding in the brain occurs, it is considered a medical emergency.
Hemophilia B symptoms can be mild, moderate, or severe. The severity is determined by the amount of clotting factor in the blood. About 50 percent of people with hemophilia B have the severe form, 30 percent have the moderate form, and 20 percent have the mild form.
People who do not have hemophilia B have a factor 9 activity of 100 percent. People with severe hemophilia B have a factor 9 activity of less than 1 percent. People with the moderate form have a factor 9 activity of between 1 and 5 percent. People with mild symptoms have a factor 9 activity of between 5 and 30 percent.
(Click Hemophilia Symptoms to learn more.)
A doctor considering a hemophilia B diagnosis will typically need to:
- Review the patient's personal and family medical history
- Perform a physical examination
- Order blood tests.
The tests will indicate:
- Whether there is a bleeding problem
- If the problem is due to hemophilia B or another cause
- How severe the disorder is.
(Click Diagnosing Hemophilia for more information.)