Laboratory Test Reference Guide

Samples should be taken 3-5 hours post-dose (subcutaneous LMWH), 4 hours post-dose (Rivaroxaban), for specimens drawn 4-6 hours subsequent to the heparin's subcutaneous injection (unfractionated heparin) 

500uL double spun platelet poor plasma

Send frozen

Rivaroxaban

There is no established therapeutic range for Rivaroxaban (Xarelto). Plasma Rivaroxaban concentration drops after dose administration and the assay result has to be interpreted in the context of the last dose. Note that routine Rivaroxaban monitoring is not recommended and the levels should not be used for tailoring doses.

ASTH (2013) recommends the following mean peak and trough levels for 20mg once daily (od):

Peak Trough
20mg od 170-400ug/L 1-150ug/L

 UNF and Clexane 

"Unfractionated Heparin Anti-Xa results should be judged in correlation with dose and timing of sample collection. Therapeutic ranges of heparin are: LMWH: 0.5-1.2 IU/mL & UH: 0.3-0.7 IU/mL

Prophylactic ranges of heparin are: LMWH: 0.2-0.5 IU/mL & UH: 0.1-0.4 IU/mL

In children under age 8 weeks, the therapeutic ranges of heparin are:

Standard heparin (UH): 0.3-0.7 IU/mL & LMWH: 0.5-1 IU/mL (for specimens drawn 4-6 hours subsequent to the heparin's subcutaneous injection)

In children under age 8 weeks, the prophylactic range of heparin:

LMWH: 0.1-0.3 IU/mL"

500uL double spun platelet poor plasma