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Test Code RIVA Rivaroxaban Level by Anti-Xa

Specimen Type

Blood

Container

Light blue top tube, 3.2% sodium citrate

Preferred Volume

2.7 mL

Offsite Collection Instructions

The blood sample should be ordinarily collected 2 to 3 hours following administration of rivaroxaban, since this is the usual time required to reach peak plasma levels.

  • Samples must be centrifuged at >1500 x g for 10 minutes at room temperature.
  • Carefully remove the plasma from the cells using a plastic transfer pipette avoiding the buffy coat.
  • Dispense the plasma into a plastic tube (glass is not acceptable) and centrifuge the plastic tube for a second centrifugation at >1500 x g for 10 minutes at room temperature.
  • Remove the top portion of the plasma being careful to leave a small amount of plasma at the bottom of the tube undisturbed (about 250mL). Then, aliquot the removed plasma into 2 plastic tubes containing minimum of 500 uL of specimen each.
  • The plasma samples must then be frozen at -20ºC.
  • Once solidly frozen they must be shipped on dry ice. Samples that have thawed in transit will be rejected.

Note: For clients who do not have access to dry ice do not freeze the specimen. Follow the centrifugation instructions or send whole blood sample. It now becomes vital that the specimen arrives in the lab within three hours of collection.

UCMC Collection Instructions

The blood sample should be ordinarily collected 2 to 3 hours following administration of rivaroxaban, since this is the usual time required to reach peak plasma levels.

 

Test is offered 7 days a week from 8:00 am until 10:30 pm. Samples that arrive after 10:30 pm will be frozen and run the next morning.

Availability

Specimens may be collected and sent to the laboratory at any time. Testing is performed 7 days a week from 8:00 am to 10:30 pm. Samples that arrive after 10:30 pm will be frozen and run the following day.

Turnaround Time

8 hours

STAT Availability

Not Available

Test Methodology

Chromogenic

Additional Information

 Rivaroxaban is monitored by a functional anti-Xa assay.
 

The blood sample should be ordinarily collected 2 to 3 hours following administration of rivaroxaban, since this is the usual time required to reach peak plasma levels.
 

Test is offered 7 days a week from 8:00 am until 10:30 pm. Samples that arrive after 10:30 pm will be frozen and run the next morning.
 

Peak steady-state plasma concentrations are typically reached approximately 2 to 3 hours following oral administration. Rivaroxaban peak concentrations of 160-360 ng/mL and trough concentrations of 4.3-95.7 ng/mL have been reported in patients taking rivaroxaban 20 mg once daily (Thromb Haemost 2008; 100:453-461); however, actual target goals depend upon intended anticoagulation intensity and dosing schedules for the individual patient.   
 

This test was validated by the University of Chicago Medicine Coagulation Laboratory.  This test has not been cleared or approved by the FDA. The laboratory is regulated under CLIA as qualified to perform high-complexity testing.

 

All 3.2% sodium citrate light blue top tubes require a ratio of 9 parts blood to 1 part anticoagulant (example: a 3.0 mL tube requires 2.7 mL blood added to 0.3 mL of anticoagulant).

CPT Code

80299

Minimum Volume

2.7 mL

Fee Code

30280299

Synonyms

Xarelto
Anti-Xa