Heparin Anti-Xa, Low Molecular Weight Heparin
Also known as: HA LMW
Use
The Heparin Anti-Xa, Low Molecular Weight Heparin test is designed to monitor the treatment efficacy of low molecular weight heparin, such as enoxaparin. It is used to ensure therapeutic dosing by measuring the activity of the anticoagulant in the patient's plasma, helping to prevent complications such as thromboembolic events while avoiding excessive anticoagulation.
Special Instructions
This test requires careful handling of specimens as outlined in ARUP's hemostasis/thrombosis guidelines. Sodium citrate tubes must be used and specimens must be centrifuged within one hour to obtain platelet-poor plasma. Appropriate storage and transportation at frozen temperatures are crucial to maintain specimen integrity.
Limitations
The test is specifically for low molecular weight heparin and cannot be used to quantitate other anticoagulants, including direct oral anticoagulants and fondaparinux (Arixtra). Improper specimen collection or handling, such as the use of EDTA, oxalate, or heparin tubes, or incomplete separation of plasma, will result in test rejection due to potential inaccuracies. Additionally, specimens that are hemolyzed, refrigerated for more than eight hours, or inadequately frozen will compromise test results.
FDA ApprovedNew York Approved
Methodology
Chromogenic Assay
Biomarkers
LOINC Codes
- 3274-8
Result Turnaround Time
1-2 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
2 mL
Minimum Volume
1.5 mL
Container
Lt. blue (sodium citrate) tube
Collection Instructions
Centrifuge specimen within one hour of collection to obtain platelet-poor plasma.
Storage Instructions
Transport plasma frozen.
Causes for Rejection
Serum, EDTA, oxalate, heparin, or plasma separator tubes; refrigerated for more than eight hours; hemolyzed specimens.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Unacceptable |
| Refrigerated | Unacceptable |
| Frozen | 1 month |