Routine: 2 Hours
Urgent: 1 Hour

24 hours, 7 days a week.

3.2% sodium citrate tubes are acceptable provided they are filed to the line on the manufacturers label. Tubes must be full (see comments below). Whole blood specimens are stable for up to 4 hours.

For referral testing to Mayo (Opens in a new window), submit at least 1.0 mL frozen platelet-poor citrated plasma. Remove plasma from cells as soon as possible and no later than 4 hours post-draw.

OHSU clinics must cab specimen to the Core Lab, Hatfield Research Center (HRC), if processing is delayed or not possible on site. Detailed instructions are included in this manual under Specialized Lab Services, Hemostasis & Thrombosis section (Opens in a new window).

Add blood to the 1.3 mL mark of Pediatric BLUE top tube, 3.2% sodium citrate.

Table taken from Mayo Clinic Laboratories Apixaban, Anti-Xa Test Catalog.  Feb 2022.

Routine monitoring of apixaban is not indicated. Therapeutic reference ranges have not been established, however, peak and trough levels observed in clinical trials at different dosing are available. Apixaban concentration may be affected by drug interactions and liver or renal disease.

Anticoagulants other than Apixaban will interfere with this test, including but not limited to:  Unfractionated Heparin, Low Molecular Weight Heparin, Rivaroxaban (Xarelto), Edoxaban (Savaysa), and Fondaparinux (Arixtra).

Other sample conditions that may interfere with this test include moderate/marked hemolysis hemolysis (hemoglobin greater than 300 mg/dL), gross icterus (bilirubin greater than 20 mg/dL) and gross lipemia (triglycerides greater than 800 mg/dL).

Draw volume is critical due to the liquid anticoagulant. Allow tubes to fill by vacuum to the fill line indicated by the tube label.

If drawing with syringe, do not remove vacutainer stopper, insert needle through stopper and allow tube to fill, by vacuum. Do not overfill vacutainer.

Anti Xa
Anti-Xa
Eliquis
FAPIX