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Factor IX Activity

FIX Factor 9 Factor IX:C
Sodium citrate (blue top) % (IU/dL)

About this test

Serine protease activated in the intrinsic pathway. Deficiency causes haemophilia B (Christmas disease). Clinical severity similar to haemophilia A.

Reference Ranges

Sex Age Range Notes
All ≥ 18 yrs 50 – 150 Adult

Clinical Interpretation

Low / Decreased
Haemophilia B — severe <1%; moderate 1–5%; mild 5–40%.
Specimen
Sodium citrate (blue top)
Reporting Unit
% (IU/dL)
Category
🩹 Coagulation

⚠ Clinical Note
Reference ranges are indicative. Always interpret results in the context of the individual patient and local laboratory reference intervals, which may vary.