How Is Hemophilia Diagnosed?

If you or your child appears to have a bleeding problem, your doctor will ask about your personal and family medical histories. This will reveal whether you or your family members, including women and girls, have bleeding problems. However, some people who have hemophilia have no recent family history of the disease.

You or your child also will likely have a physical exam and blood tests to diagnose hemophilia. Blood tests are used to find out:

  • How long it takes for your blood to clot
  • Whether your blood has low levels of any clotting factors
  • Whether any clotting factors are completely missing from your blood

The test results will show whether you have hemophilia, what type of hemophilia you have, and how severe it is.

Hemophilia A and B are classified as mild, moderate, or severe, depending on the amount of clotting factor VIII or IX in the blood.

Mild hemophilia 5–40 percent of normal clotting factor
Moderate hemophilia 1–5 percent of normal clotting factor
Severe hemophilia Less than 1 percent of normal clotting factor

The severity of symptoms can overlap between the categories. For example, some people who have mild hemophilia may have bleeding problems almost as often or as severe as some people who have moderate hemophilia.

Severe hemophilia can cause serious bleeding problems in babies. Thus, children who have severe hemophilia usually are diagnosed during the first year of life. People who have milder forms of hemophilia may not be diagnosed until they're adults.

The bleeding problems of hemophilia A and hemophilia B are the same. Only special blood tests can tell which type of the disorder you or your child has. Knowing which type is important because the treatments are different.

Pregnant women who are known hemophilia carriers can have the disorder diagnosed in their unborn babies as early as 12 weeks into their pregnancies.

Women who are hemophilia carriers also can have "preimplantation diagnosis" to have children who don't have hemophilia.

For this process, women have their eggs removed and fertilized by sperm in a laboratory. The embryos are then tested for hemophilia. Only embryos without the disorder are implanted in the womb.



Source: National Heart, Lung, and Blood Institute, National Institutes of Health.