Hemophilia B: Causes, Symptoms, Diagnosis, and Treatment

Diagnosis of Hemophilia B

Diagnosing Hemophilia B involves a combination of family history, physical examination, and laboratory tests to measure clotting factor levels. The key tests include:

• Activated Partial Thromboplastin Time (aPTT): Measures how long blood takes to clot. It is prolonged in Hemophilia B.
• Factor IX Activity Test: Determines the level of factor IX in the blood, confirming the diagnosis.
• Genetic Testing: Identifies mutations in the F9 gene, which can be useful for confirming the diagnosis and for carrier screening in families with a history of Hemophilia B.

Newborns with a family history of hemophilia may be tested at birth to determine their factor IX levels.