Mar 20, 2017




Clinical Hub,Tools & Resources,UWHC Lab Test Directory,Coagulation

Apixaban by anti-Xa

Apixaban by anti-Xa (APIX) Coagulation Lab Test

Name: Apixaban by anti-Xa

Test Name: Apixaban by anti-Xa

Health Link Test Code: APIX

LIS Test Code: APIX

CPT Code(s): 85300

Methodology: Chromogenic Anti-Xa Assay

Clinical Information:

The plasma level of Apixaban is determined by the measurement of anti-Xa activity.

Days Performed: Daily- Specimens are accepted at any time. Testing required during off hours must be approved by a Coagulation physician. Call (608)263-5005 before collection.

In-Lab Turnaround Time: 1 day.

Stat In-Lab Turnaround Time: 2 hours.

Specimen: Blood

Collection Container: Light blue top (3.2% NaCitrate)

Collection Instructions:

Do NOT draw through a line containing heparin as this method is unable to distinguish Apixaban from hepain in the sample. The venipuncture MUST be atraumatic to avoid hemolysis and contamination with tissue factors and platelets.

Collection Volume: Full 3.5 mL tube

Pediatric Collection Volume: Pediatric tube filled to fill mark

Stability Ambient:

2 hours off cells

Stability Refridgerated:

Not acceptable

Stability Frozen:

3 months at -70°C

Sample Analyzed: Plasma

Testing Volume: 0.5 mL

Pediatric Testing Volume: 0.3 mL

Specimen Processing:

Centrifuge specimen to yield platelet poor plasma (platelet count of plasma should be less than 10K/µL). Separate plasma and transfer to plastic tube or vial. Freeze plasma at -200C or below.

Specimen Transport:

Transport whole blood specimens at room temperature to UWHC Hospital Laboratory within 2 hours of collection. See Specimen Processing for instructions if transport criteria are not able to be met. Transport frozen plasma aliquot on dry ice to UWHC Hospital Laboratory.

Unacceptable Criteria:

Hemolyzed specimens, clotted specimens, partially filled tubes and whole blood specimens greater than 2 hours old when received by the laboratory are not acceptable.


For Apixaban, no "therapeutic range" has been established. Observed peak (3-4hrs) and trough concentrations patients exposed to therapeutic dosing are as follows:

Stroke prevention in AF:

Peak values: 2.5mg bid: 69-221ng/mL, 5mg bid: 91-321ng/mL

Trough values: 2.5mg bid: 34-162ng/mL, 5mg bid: 41-230ng/mL


VTE treatment:

Peak values: 2.5mg bid: 30-153ng/mL, 5mg bid: 59-302ng/mL, 10mg bid: 111-572ng/mL

Trough values: 2.5mg bid: 11-90ng/mL, 5mg bid: 22-177ng/mL, 10mg: 41-335ng/mL


VTE prophylaxis:

Peak value: 2.5mg bid: 41-146ng/mL, trough value: 23-109ng/mL


The performance characteristics of this test were validated by the UWHC Clinical Laboratories. The U.S. Food and Drug Administratin (FDA) has not approved or cleared this test, however, FDA approval or clearance is currently not required for clinical use of this test. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. The UWHC Clinical Improvement Amendments (CLIA) to perform high-complexity testing.