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)
Chromogenic Assay
Eliquis
Plasma Na Cit
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).
If priority specimen, mark request form, give reason, and request a call-back.
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 degrees C or, ideally, < or =-40 degrees 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.
If not ordering electronically, complete, print, and send a Coagulation Test Request (T753) with the specimen.
0.5 mL
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Plasma Na Cit | Frozen | 42 days |
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)
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)
Dosage | Apixaban C-min (ng/mL) trough plasma concentration (predose) | Apixaban C-max (ng/mL) peak plasma concentration |
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
<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.
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.
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
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
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
The apixaban, anti-Xa assay is performed on the Instrumentation Laboratory ACL TOP 700 using the HemosIL Liquid Anti-Xa kit. The liquid Anti-Xa kit is a 1-stage chromogenic assay based on a synthetic chromogenic substrate and on factor Xa inactivation. Factor Xa is neutralized directly by apixaban. Residual factor Xa is quantified with a synthetic chromogenic substrate. The paranitroaniline released is monitored kinetically at 405 nm and is inversely proportional to the apixaban in the sample.(Package insert: HemosiL Liquid Anti-Xa kit. Instrumentation Laboratory Company; REV 06/2017)
Monday through Friday
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.
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
APIXA | Apixaban, Anti-Xa, P | 74214-8 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
APIX1 | Apixaban, Anti-Xa, P | 74214-8 |
APIX2 | Interpretation | 69049-5 |
APIX3 | Cautions | 62364-5 |