Therapeutic monitoring of warfarin in patients on bivalirudin

Bivalirudin elevates prothrombin time/INR. For an accurate assessment of warfarin effect in patients on current bivalirudin, use Chromogenic Factor X monitoring.


Used instead of INR to monitor warfarin in patients with antiphospholipid antibodies that might interfere with INR, or in patients on concurrent direct thrombin inhibitors that might interfere with INR.

  • Therapeutic range for warfarin:

    • CFX 35-27% = INR 2-3

    • CFX 31-25% = INR 2.5-3.5

    • CFX 27-24% = INR 3-4

  • Test order code: CHRF10
  • Specimen collection: 3mL or 5mL light top tube (citrate)