Antifactor Xa Heparin Dosing Protocol

This protocol is used where heparin monitoring with aPTT is not possible such as in antiphospholipid antibody syndrome or deranged baseline coagulation parameters.
An anti Xa level must be obtained within 24 hours prior to heparin initiateion.
Bolus and target are dependent upon indication for anticoagulation as noted below.
Standard heparin for DVT/PE starts with a bolus of 80 units/kg up to 10,000 units.
Standard heparin for DVT/PE has an initial infusion of 18 units/kg/hr up to 2,000 units/hour.
Acute coronary syndrome or low dose heparin starts with a bolus of 60 units/kg up to 4,000 units.
Acute coronary syndrome or low dose heparin has an initial infusion of 12 units/kg/hr up to 1,000 units/hour.
Stroke or no bolus heparin has no initial bolus.
Stroke or no bolus heparin has an initial infusion of 12 units/kg/hr up to 1,000 units/hour.
Goal antifactor Xa is 0.3-0.7 for all three protocols.
The first antifactor Xa is obtained 6 hours after initial infusion is started.
Antifactor Xa levels are obtained six hours after a dosage change.
If heparin dose is not changed, antifactor Xa levels are obtained daily.
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