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 classed as severe, moderate or mild depending on how much clotting factor is missing. 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 with haemophilia.

ClassificationLevel of factor VIII or factor IX in the blood
(normal: 50-150%)
Typical bleeding tendency
SevereLess than 1% of normal levelEasy 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.  
Moderate1 to 5% of normal levelEasy bruising.  
Bleeding because of minor injury.  
Occasional spontaneous bleeding.  
Likely to have problems after having dental or surgical procedures and/or a bad injury.
MildOver 5% of normal levelEasy bruising  
Bleeding usually only occurs following injury, surgical or dental (tooth extraction) procedures.  
Might never have a bleeding problem requiring medical attention. Might not be diagnosed until later in life if not playing contact sports or have not had any injuries or operations.  
Females may also have heavy or prolonged periods (menorrhagia).

More information is available in our Understanding Haemophilia booklet.