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| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
HEPARIN ANTI Xa
Test CodeANTIXa
Alias/See Also
Factor Xa
Preferred Specimen
Blue Tube (Sodium Citrate)
If a butterfly needle is use for collection, a NON-ADDITIVE discard tube must be drawn first
If a butterfly needle is use for collection, a NON-ADDITIVE discard tube must be drawn first
Patient Preparation
The anti-Xa level should be drawn 4 hours after a dose of Enoxaparin is given, once at steady state (at least 3 doses given on time).
This test cannot be used to monitor Rivaroxaban (Xarelto) or Fondaparinux (Arixtra) therapy.
Minimum Volume
2 mL (Tube MUST be filled to nominal line for proper whole blood to anticoagulant ratio – see volume guides below)
Other Acceptable Specimens
None
Instructions
Upon collection, mix by gentle inversion 6 times. Centrifuge specimen within one hour of collection.
Lab note: Refer to document below (Obtaining a Platelet-Poor Specimen)
Lab note: Refer to document below (Obtaining a Platelet-Poor Specimen)
Transport Container
Blue Tube
Transport Temperature
Room Temperature
Specimen Stability
- Plasma separated from cells is stable at 15-30°C up to 4 hours
- -20°C up to 2 weeks
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
The following conditions will result in a rejected sample:
- Serum, EDTA Oxalate, Heparin, or Plasma separator tubes
- Specimens ambient (room temperature) more than 4 hours
- Hemolyzed, icteric, or lipemic specimen
- Specimen submitted refrigerated
- Whole blood specimens not centrifuged within 4 hours
Methodology
Chromogenic Assay
Setup Schedule
DAILY, as received
Report Available
STAT: <60 minutes
Routine: <4 hours
Routine: <4 hours
Reference Range
| Dosing (Enoxaparin) | Therapeutic Ranges |
| Therapeutic, twice daily dosing | 0.5 - 1.0 IU/mL |
| Therapeutic, once dialy dosing | 1.0 - 2.0 IU/mL |
| Prophylactic | 0.2 - 0.6 IU/mL |
Clinical Significance
Assay can be used to monitor patients on Fragmin, Innohep, Lovenox and Fraxiparine.
If the Heparin Anti-Xa result is high, the patient 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.
If the Heparin Anti-Xa result is high, the patient 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.
Performing Laboratory
Mount Sinai Hospital
Additional Information
BD Vacutainer Blue Top Volume Guide
Greiner Vacutainer Blue Top Volume Guide
Obtaining A Platelet-Poor Specimen
