Hemostasis Reference Laboratory

Factor IX Activity

• Transaction Code: 3210-14
• CPT Code (Suggested): 85250

A one-stage intrinsic system clotting assay is used to measure circulating factor IX levels. Clotting times of dilutions of patient plasma are compared to dilutions of a plasma pool from normal donors, when added to deficient plasma. Levels are reduced by hereditary (Hemophilia B) or acquired factor IX deficiency, factor IX inhibitor, vitamin K deficiency, warfarin therapy, or liver disease.

• 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 Range: 68-132% effective 11/1/11
• Analytic Time: Performed weekly, available STAT