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HelpTest Code LABAPIXA Apixaban, Anti-Xa, Plasma
Additional Codes
| Test Name in EPIC | EPIC Test Code | Mnemonic |
|---|---|---|
| Apixaban, Anti-XA | LABAPIXA | APIXA |
Useful For/Utility
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)
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).
Specimen Type
3.2% Na Citrate plasma
Specimen Required
Fill Blue top tube to the etched line located just below the cap of the tube.
Additional Information:
1. Specimen should be collected 2 to 4 hours (peak) after a dose or just prior (trough) to the next dose for rivaroxaban concentrations.
Unacceptable specimens: Specimens that are short-draws, over-draws, clotted, or hemolyzed may yield incorrect results.
Specimen Stability Information
Double-centrifuged specimens are critical for accurate results as platelet contamination may cause spurious results.
1. To achieve platelet-poor plasma, spin down, remove top 2/3 of plasma, and spin plasma again in a plastic vial.*
2 Aliquot top 3/4 and place platelet-poor plasma in a plastic transport vial.*
3. Glass vials are not acceptable for processing/transport/storage.
4. Preferred specimen volume: 1 mL sodium citrate plasma
* 2 Aliquot labels will auto print at non-performing sites to double spin
If there is a delay in transport of >2 hours, send specimen frozen.
Method and Method Description
Chromogenic Assay
The apixaban, anti-Xa assay is performed on the Instrumentation Laboratory ACL TOP Family 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)
Performing Laboratory
SMDC Clinical Laboratory
Clinical Information
Apixaban, Anti-Xa
Therapeutic reference ranges have not been established. Target “on-therapy” ranges are based on peak and trough drug concentrations observed in clinical trials. Apixaban concentration may be affected by drug interactions and liver or kidney disease.
This result should not be the sole indicator to determine the safety and effectiveness of anticoagulation. Consider dose timing, renal function, bleeding/thrombotic risk, and clinical context.
This assay is not indicated for monitoring low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH) concentrations.
Predicted Apixaban Steady-State Exposure Concentrations
| 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)
Abbreviations not previously defined:
Nonvalvular atrial fibrillation (NVAF)
Deep vein thrombosis (DVT)
Pulmonary embolism (PE)
Day(s) Performed
Monday-Sunday
CPT Code Information
CPT: 80299
LOINC Code Information
Order and result LOINC: 74214-8