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Factor VIII Activity

FVIII Factor 8 Factor VIII:C
Sodium citrate (blue top) % (IU/dL)

About this test

Pro-coagulant cofactor for FIX in the intrinsic pathway. Deficiency causes haemophilia A. Measured to diagnose haemophilia A, vWD (where FVIII can be secondarily low), and in acquired factor VIII inhibitor syndrome.

Reference Ranges

Sex Age Range Notes
All ≥ 18 yrs 50 – 150 Adult (50–150% of normal pooled plasma)

Clinical Interpretation

Low / Decreased
Severe haemophilia A <1%; moderate 1–5%; mild 5–40%. Also low in vWD (particularly type 3) and acquired haemophilia A.
High / Increased
Elevated — acute-phase response, post-surgery, pregnancy, OCP.
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.