anti - Factor - Xa activity
General information:
Anti-Xa Activity Test (Anti-Factor Xa Assay) is a laboratory test used to measure the effectiveness of anticoagulant therapy, especially with low molecular weight heparins (LMWH) such as enoxaparin, nadroparin (Fraxiparine), or fondaparinux.
It quantifies the inhibition of Factor Xa, a key enzyme in the blood clotting process. The test shows how much the anticoagulant is working in the patient's body.
When is it performed?
Typically, the blood sample is taken 4 hours after subcutaneous injection of the anticoagulant, when its concentration peaks
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To monitor and adjust dosage in patients at high risk of thrombosis or bleeding.
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Especially important in pregnant women, patients with renal impairment, obesity, or extreme body weight.
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To ensure safe and effective anticoagulation without causing complications.
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Prophylactic dose: 0.2–0.4 U/ml
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Therapeutic dose: 0.5–1.2 U/ml
These values may vary depending on the specific medication and clinical context.
The laboratory does not support Factor Xa activity testing for patients taking oral anticoagulants such as Rivaroxaban (Xarelto), Edoxaban (Lixiana), or Apixaban (Eliquis).
Venous blood
Key words:
Anti - factor- Xa activity