Hemostasis Reference Laboratory

Factor X Activity

• Transaction Code: 3210-15
• CPT Code: 85260

A one-stage extrinsic system clotting assay is used to measure circulating factor X 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 in hereditary or acquired factor X deficiency, factor X inhibitor, vitamin K deficiency, warfarin therapy, liver disease, disseminated intravascular coagulation (DIC), or amyloidosis. With special arrangement, intrinsic system and Russell’s viper venom (RVV) activations can be added for comparison.

• 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: 64-135% effective 11/1/11
• Analytic Time: Performed weekly, available STAT