Hemostasis Reference Laboratory

Specific Factor Inhibitor Titer (Other than Factor VIII)

• Transaction Code: 3220-02
• CPT Code (Suggested): 85335

Dilutions of patient plasma are incubated with normal plasma and the specific factor assay determined.

Factor VIII inhibitors, IgG antibodies directed against factor VIII, can occur in alloimmunized patients with congenital factor VIII deficiency (Hemophilia A) or as autoantibodies. The latter are associated with pregnancy, autoimmune disease, or drugs but most often occur spontaneously, particularly among elderly persons.

• Sample Required: 0.5 ml frozen plasma x4 or (2) 3.2% sodium citrated tubes, 5 ml each.
• See Sample Requirements when ordered with other tests.
• Normal Test Value: None detected (values reported in Bethesda units)
• Analytic Time: Run about twice a month; available sooner if pre-approved