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Test Code AXA Anti-Xa

Important Note

Direct outpatients to a hospital outpatient collection laboratory.  Testing must occur within 2 hours of collection or sample must be frozen.

EHR Test Codes

  Test Code Test Name
Atlas AXA Anti-AXA
Cerner AXA Anti-Xa

 

Specimen Requirements

Preparation of Patient: 

None

 

Container Type:

Light Blue Top 3.2% Sodium Citrate Tube 4.5 mL, 3.0 mL, 2.7 mL, 2.0 mL, or 1.8 mL

Specimen Type:

Plasma platelet poor

 

Specimen Volume:

Fill tube completely.  Less than 90% filled tubes will be rejected.

 

Special Instructions:

For patients who are difficult access, < 1 year, and/or have a hematocrit > 55.9%; special tubes with an adjusted amount of anticoagulant can be prepared to allow for proper blood/anticoagulant ratio for accurate testing.  Call the Hematology lab at 231-935-6118 to request special tube.

 

Specimen Handling/Transport:

Do not centrifuge.  Do not refrigerate.  Deliver to laboratory immediately.

Transport ambient room temperature.

 

Special Instructions: 

If a specimen cannot be tested within 2 hours of draw, plasma should be removed from the cells and preserved as follows: Spin in a centrifuge verified for platelet-poor plasma preparation, remove plasma to a plastic tube, spin the plasma a second time, then remove plasma to a screw-top plastic  tube and freeze immediately at -20° C. Transport frozen.

 

Specimen Storage/Stability:

Whole blood ambient room temperature 2 hours. 

Double spun plasma aliquot ambient room temperature 1 hours.

Double spun plasma aliquot frozen -20° C 14 days.

 

Specimen Rejection:

Less than 90% filled tubes

Hemolysis

Clotted

Performing Laboratory

Munson Medical Center Laboratories

Coagulation Department

Priority, Frequency, & Turnaround

Priority:

STAT, ASAP, Non-Emergent

 

Frequency:

24 hours 7 days a week

 

Turnaround:

0 - 1 days

STAT 60 minute from receipt in lab

Methodology

Competitive Assay Using Synthetic Chromogenic Substrate

Reporting

Reference Range:

0.5 - 1.0 IU/mL 

 

Interpretive Data:

LMWH twice daily dosing Therapeutic goal 0.50-1.00 IU/mL with sample obtained 4-6 hours post dose. LMWH once daily dosing Therapeutic goal 1.00-2.00 IU/mL with sample obtained 4-6 hours post dose. Unfractionated Heparin Therapeutic Goal 0.30-0.70 IU/mL. Unfractionated Heparin post TNKase for STEMI Only 0.20-0.35 IU/mL.
 

Critical Decision: 

≥ 2.00 IU/mL

Note:  Critical values are called to the provider and communicated as critical.  Documentation of the call is recorded in the patient record.

Clinical Significance

Heparins (UFH and LMWH) are used for the prevention and treatment of throboembolic diseases.  The quantitative determination of the heparin anti-Xa activity is useful tool for monitoring treatment efficacy.

 

Low molecular weight heparin is monitored using the Heparin Anti-factor Xa in the clinical scenarios below.

 

Monitoring unfractionated heparin therapy in patients with: factor deficiencies, known antithrombin deficiency, heparin resistance due to acute phase reactants, pregnancy or drugs, antiphospholipid antibodies.

 

Monitoring low molecular weight heparin therapy in patients with: renal failure, hepatic failure, obesity or low body weight, pregnancy, long-term low molecular weight heparin therapy, complicated coagulation issues.

 

Monitoring pediatric patients on low molecular weight heparin.

CPT Code(s)

85520