Anti-factor Xa Heparin: Reference Range

Anti-factor Xa Heparin is used to monitor standard, unfractionated heparin (UFH) therapy and sometimes to monitor low molecular weight heparin (LMWH) therapy.

The target anti-Xa range for unfractionated heparin:

Therapeutic range (high intensity anticoagulation) = 0.3 to 0.7 Units/mL
Prophylactic range (low intensity anticoagulation) = 0.1 to 0.4 Units/mL

The range may vary slightly among different labs.

If test results are within an established therapeutic range and the person is doing well clinically, the dosage is considered appropriate.

If the heparin anti-Xa result is high, then the person may be getting an excessive dose and/or not be clearing the drug at an expected rate and may be at an increased risk for excessive bleeding.

If the heparin anti-Xa result is below the therapeutic range, then the dosage of heparin may need to be increased to prevent excessive clotting.

Keywords: Anti-factor Xa Heparin, Anti-FXa, Anti-Xa chromogenic, Heparin Activity, Heparin Anti-Xa, Heparin Level, Xa Inhibition

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.