Apixaban anti-Xa

Alphabetical Test listing

Apixaban anti-Xa-994

Apixaban anti-Xa

To measure plasma apixaban concentration in ng/mL.

Sodium citrate (Na cit) plasma
1.0 mL
0.5 mL

Immediatley following collection, mix sample by gentle inversion 3 - 4 times to prevent clotting

  1. Spin
  2. Transfer plasma to a Screw-cap polypropylene frozen transport vial/tube - 4mL (LabCorp), labelled as Na citrate plasma, within two (2) hours of sample collection
  3. Freeze within six (6) hours of sample collection

Frozen (preferred)

Freeze/thaw cycles: stable x6

Ambient - 6 hours

  • Gross hemolysis
  • Gross lipemia
LabCorp Burlington (504385): R-NX
Mo - Fr
2 - 5 days

Chromogenic anti-Xa. Apixaban inhibition of factor Xa (present in excess). Residual Xa is measured using a chromogen and is inversely proportional to the apixaban present.


Although routine monitoring is not needed, there are a number of clinical circumstances in which clinicians want or need to know a patient's Apixaban level. Levels can be accurately and precisely measured using either a chromogenic anti-Xa assay or LC/MS-MS.