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Test ID: APIXA Apixaban, Anti-Xa, Plasma

Ordering Guidance

This assay is not indicated for monitoring low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH) concentrations. The presence of UFH and LMWH will cause the apixaban anti-Xa level to be falsely elevated.


This assay is optimized to measure apixaban concentration in presence of coagulation factor Xa recombinant, inactivated-zhzo (andexanet alfa, Andexxa).

Necessary Information

If priority specimen, mark request form, give reason, and request a call-back.

Specimen Required

Specimen Type: Platelet-poor plasma

Collection Container/Tube: Light-blue top (3.2% sodium citrate)

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. Specimen should be collected 2 to 4 hours (peak) after a dose or just prior (trough) to the next dose for apixaban concentrations.

2. For complete instructions, see Coagulation Guidelines for Specimen Handling and Processing in Special Instructions.

3. Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again.

4. Aliquot plasma into a plastic vial leaving 0.25 mL in the bottom of centrifuged vial.

5. Freeze plasma immediately (no longer than 4 hours after collection) at -20° C or, ideally, ≤-40° C.

Additional Information:

1. A double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.

2. Each coagulation assay requested should have its own vial.

Useful For

Measuring apixaban concentration in selected clinical situations (eg, renal insufficiency, assessment of compliance, periprocedural measurement of drug concentration, suspected overdose, advanced age, and extremes of body weight)

Method Name

Chromogenic Assay

Reporting Name

Apixaban, Anti-Xa, P

Specimen Type

Plasma Na Cit

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma Na Cit Frozen 42 days

Clinical Information

Apixaban, an oral anticoagulant that directly inhibits factor Xa, has been approved by the FDA for prophylaxis of thrombosis in atrial fibrillation and surgical patients and treatment of venous thromboembolism (VTE). Unlike warfarin, it does not require routine therapeutic monitoring. However, in selected clinical situations, measurement of drug level would be useful (eg, kidney insufficiency, assessment of compliance, periprocedural measurement of drug concentration, suspected overdose, advanced age, and extremes of body weight).


Predicted Apixaban Steady-State Exposure Concentrations(1)



C-min (ng/mL)

trough plasma concentration (predose)

Apixaban C-max (ng/mL)

peak plasma concentration
(2-4 hours postdose)

Prevention of VTE: elective hip or knee replacement surgery



2.5 mg twice daily

51 (23-109)

77 (41-146)

Prevention of stroke and systemic embolism: NVAF



2.5 mg twice daily

79 (34-162)

123 (69-221)

5 mg twice daily

103 (41-230)

171 (91-321)

Treatment of DVT, treatment of PE and prevention of recurrent DVT and PE (VTE)



2.5 mg twice daily

32 (11-90)

67 (30-153)

5 mg twice daily

63 (22-177)

132 (59-302)

10 mg twice daily

120 (41-335)

251 (111-572)


Median (5th-95th percentile)

VTE-venous thromboembolism, NVAF- nonvalvular atrial fibrillation, DVT-deep vein thrombosis, PE-pulmonary embolism

Reference Values

<10 ng/mL


The lower limit of detection of this assay is 10 ng/mL.


Therapeutic reference ranges have not been established. See Clinical Information for peak and trough drug concentrations observed from clinical trials.

Clinical Reference

1. Eliquis (apixaban). Package insert. Bristol-Meyers Squibb Company; Revised 11/2019

2. Hurst KV, O'Callaghan JM, Handa A: Quick reference guide to apixaban. Vasc Health Risk Manag. 2017;13:263-267

3. Granger CB, Alexander JH, McMurray JJ, et al: Apixaban versus warfarin in patient with atrial fibrillation. N Engl J Med. 2011 Sep;365(11):981-992

4. Frost C, Nepal S, Wang J, et al: Safety, pharmacokinetics and pharmacodynamics of multiple oral doses of apixaban, a factor Xa inhibitor, in healthy subjects. Br J Clin Pharmocol. 2013 Nov;76:(5):776-786

5. Agnelli G, Buller HR, Cohen A, et al: Oral apixaban for the treatment of acute venous thromboembolism. N Engl J Med. 2013 Aug 29;369(9):799-808

6. Siegal DM, Curnutte JT, Connolly SJ, et al: Andexanet alfa for reversal of factor Xa inhibitor activity. N Engl J Med. 2015 Dec 17;373:2413-2424

7. Martin K, Beyer-Westendorf J, Davidson BL, Huisman MV, Sandset PM, Moll S: Use of the direct oral anticoagulants in obese patients: guidance from the SSC of the ISTH. J Thromb Haemost. 2016 Jun;14(6):1308-1313

Day(s) Performed

Monday through Friday

Report Available

1 to 3 days

Test Classification

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
APIXA Apixaban, Anti-Xa, P 74214-8


Result ID Test Result Name Result LOINC Value
APIX1 Apixaban, Anti-Xa, P 74214-8
APIX2 Interpretation 69049-5
APIX3 Cautions 62364-5
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