Investigations

 

  1. Those at risk include:
  2. Males presenting in adulthood with unexplained bleeding could have moderate or mild haemophilia
    A or B.
  3. Females who have a male relative affected with haemophilia A or B are at risk of being a carrier.
  4. Children whose mother is a carrier, or daughters of an affected father.
  5. Specialist services can provide advice regarding appropriate testing.
  6. For individuals suspected of having haemophilia A or B, investigations include:
  7. Partial thromboplastin time (PTT)
  8. Activated partial thromboplastin time (APTT)
  9. Prothrombin time (PT)
  10. In severe and moderately severe haemophilia A or B, the PTT is prolonged.
  11. In mild haemophilia A or B, the PTT is often normal.
  12. Individuals with a history of a lifelong bleeding tendency should have specific coagulation factor assays
    performed even if all the coagulation screening tests are in the normal range.
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DNA testing

  1. Patients requiring DNA testing should be referred to a specialist centre.
  2. DNA testing is indicated to assist in prenatal testing in pregnancies at risk for haemophilia A or B.
  3. DNA testing can be time consuming and, if possible, couples should be referred prior to pregnancy.
  4. Even in individuals with clinical haemophilia, a specific mutation may not be found thus prohibiting cascade testing for carrier status.
  5. Testing can be offered prenatally to women using chorionic villus sampling or amniocentesis.
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