What does severity mean?
There are three types of haemophilia: mild, moderate and severe. The level of severity depends on how much clotting factor VIII (8) or IX (9) is in the person’s blood naturally. A person with haemophilia will have the same level of severity their whole life, e.g. someone with severe haemophilia will always have severe haemophilia. Within a family, males will also inherit the same level of severity, e.g. if a grandfather has severe haemophilia and his grandson has inherited haemophilia, his grandson will also have severe haemophilia. However, this is not the same for females. For example, a girl whose father has severe haemophilia may have the same factor levels and symptoms as a girl whose father has mild haemophilia.
For a person who doesn’t have haemophilia, the range of factor VIII (8) and factor IX (9) in their blood is usually between 50% and 200%
5 – 40% of normal clotting factor
Usually only have bleeding problems after having teeth taken out, surgery or a bad injury or accident
Might never experience a bleeding problem.
1 – 5% of normal clotting factor
Might have bleeding problems after having teeth taken out, surgery or a bad injury or accident
Might have a bleed about once a month
Rarely have a bleed for no obvious reason.
Less than 1% of normal clotting factor
Often have bleeds into joints, muscles and soft tissues
Can have bleeds for no obvious reason, as well as after surgery, dental work or injuries including minor bumps or knocks
Might have a bleed once or twice a week
Date last reviewed: 21/06/2012