Anti-factor Xa level (Anti-Xa)

Definition

Anti-factor Xa level (Anti-Xa) measures the activity of factor Xa inhibitors, used to monitor and adjust anticoagulant therapy. It ensures patients are within the therapeutic range to prevent clotting or bleeding complications.

5 Must Know Facts For Your Next Test

1. Anti-Xa is primarily used to monitor low molecular weight heparin (LMWH) therapy.
2. The test helps adjust dosages of anticoagulants like enoxaparin and fondaparinux.
3. A high Anti-Xa level indicates excessive anticoagulation, increasing the risk of bleeding.
4. A low Anti-Xa level suggests inadequate anticoagulation, increasing the risk of thrombosis.
5. Anti-Xa levels are usually drawn 4 hours after a subcutaneous LMWH dose for accurate monitoring.

Review Questions

• What is the primary use of measuring Anti-factor Xa levels in patients?
• When should Anti-factor Xa levels be drawn for accurate monitoring of LMWH therapy?
• What does a high Anti-Xa level indicate in terms of patient risk?

Related terms

Low Molecular Weight Heparin (LMWH): A class of anticoagulants that includes drugs like enoxaparin, used to prevent and treat thrombosis.

Prothrombin Time (PT): A blood test that measures how long it takes blood to clot, often used to monitor warfarin therapy.

Activated Partial Thromboplastin Time (aPTT): A test that evaluates the intrinsic pathway of coagulation, commonly used to monitor unfractionated heparin therapy.