There are two main reasons to test to see if a young adult or teenage girl is a carrier. Firstly, to measure the individual\’s factor level and from this any precautions to prevent abnormal bleeding can be taken and secondly, to determine a person’s carrier status. Factor level testing (factor assay), is done to determine a person’s level of factor VIII or IX. This can help determine whether she is at greater than normal risk of bleeding. It is important to know the factor level in a potential carrier due to an increased risk for bleeding that she may experience. With low factor levels, there is increased risk of bleeding after tooth extraction, trauma or surgery.

Also, when a girl has her period there is a tendency for excessive bleeding and if the girl has very low factor levels she may require medical treatment. Carriers may also need medical intervention for nosebleeds. If levels are low, precautions can be taken to prevent many of these complications and with this in mind, testing factor levels at a young age would appear to be beneficial. In addition, if such testing is done, it should be carried out at a Comprehensive Care Centre or a Haemophilia Treatment Centre as both of these centres can collaborate with gynaecologists and GP’s in dealing with a specific case and prevent any medication being prescribed that could affect coagulation or prevent a medical procedure that may cause bleeding.

Reasons for testing in childhood

In Ireland, the policy is that the girl must be 16 years old before she is tested. The sooner a girl is tested after this age, the more time she has to come to terms with being a carrier and all the issues that are associated with it, and the sooner she can get the information necessary to help her deal with issues concerning treatment for any type of medical problem. It also prepares her for eventual decisions such as conception, pregnancy and childbirth. Genetic testing for carrier status is best done before pregnancy as factor VIII levels rise during pregnancy and tests at this stage are unreliable.

Reasons for delaying testing until adulthood

There are some arguments against carrier testing at a young age. It may affect your self-esteem and it can also affect your decisions you make regarding relationships. Some families feel the only reason to know about a carrier status is for family planning.  If genetic testing is done in childhood, the girl’s parents are usually the main source of relevant information.