Types of Haemophilia
There are two types of haemophilia:
- haemophilia A is a deficiency of factor VIII (8)
- haemophilia B (also known as Christmas Disease) is a deficiency of factor IX (9).
Both types of haemophilia have the same symptoms and are inherited in the same way, though treatment is different depending on which clotting factor is missing. Specialist blood tests are needed to measure the clotting factors to show whether factor VIII or factor IX is affected and how much is missing.
Haemophilia is classified as severe, moderate or mild depending on the missing clotting factor. The level of factor VIII or factor IX in the blood is measured by a specialist laboratory. In general, the lower the level, the more bleeding problems the affected person will have without treatment.
Females can also be affected by haemophilia.
| Classification | Level of factor VIII or factor IX in the blood (normal: 50-150%) | Typical bleeding tendency |
|---|---|---|
| Severe | Less than 1% of normal level | Easy bruising, including from mouth and nose. Bleeding into joints and muscles, which can be without obvious cause. Bleeding after dental or surgical procedures or injuries, including minor bumps and knocks. |
| Moderate | 1 to 5% of normal level | Easy bruising. Bleeding because of minor injury. Occasional spontaneous bleeding. Likely to have problems after having dental or surgical procedures and/or a bad injury. |
| Mild | Over 5% of normal level | Easy bruising, including from mouth and nose. Bleeding into joints and muscles, which can be without obvious cause. Bleeding after dental or surgical procedures or injuries including minor bumps and knocks. |
More information is available in our Understanding Haemophilia booklet.