A Blood 'How I treat' review sets out how to find and diagnose carriers of haemophilia and women and girls with haemophilia, who remain underdiagnosed. Many carriers have low factor levels and clinically important bleeding, especially heavy menstrual bleeding and bleeding after childbirth or surgery.
The authors argue for moving from testing the individual patient to testing the family: once a male relative is diagnosed, at-risk female relatives should be identified systematically. The work-up combines the pedigree, a structured bleeding assessment, factor VIII or IX activity, and genetic testing for the family variant, with counselling.
The laboratory points matter. A normal APTT does not exclude a low factor level, factor VIII rises with pregnancy, stress and oestrogen, and a single normal level does not exclude carriership. Genetic testing is the definitive answer where the family variant is known.
In India, where haemophilia care is concentrated in a limited number of centres, female relatives are rarely tested. Laboratories can help by flagging the limits of a normal screen in a woman with a family history.
- Measure factor VIII or IX activity directly in at-risk female relatives; do not rely on the APTT
- Interpret factor VIII levels cautiously in pregnancy, on oestrogen or during acute illness, and repeat if needed
- Use genetic testing for the known family variant to confirm or exclude carriership
- Ask about heavy menstrual bleeding and postpartum bleeding in female relatives of men with haemophilia
- Report factor levels with a comment on carrier interpretation when a family history is given
Why it matters
A normal screening test in a carrier can lead to unprepared surgery or childbirth.
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