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Specimen Collection
2.7 mL Citrate Blood

or

1.8 mL Citrate Blood

or

Tube must be filled to the line.

If the specimen is collected  at laboratories other then  Auckland Hospital: Send 1 x 1.5 mL  frozen plasma aliquot ( double spin plasma before freezing ), for processing the following day.

If result is required urgently, label as urgent and notify the coagulation department. ext 22069   

Filtered plasma is unsuitable and may lead to erroneously low results.

• Please state the brand of heparin being used.

1 mL Paediatric Micro-citrate Blood

• Paediatric micro-citrate samples still require to be a venous blood collect ,   finger prick collects  are unsuitable for the anti Xa testing.

 

 

 

• For routine heparin therapy control - see Activated Partial Thromboplastin Time.
  

Activated Partial Thromboplastin Time

Reference Intervals

Clexane

• 0.6 - 1.0 unit/ml for treatment of known thrombosis.
• Evidence based target range for prophylaxis not available. (Range of 0.2 - 0.6 has been quoted in some studies.)
• Uncertainty of measurement:  8%

Rivaroxaban

There is no established therapeutic PR range for rivaroxaban, but ASTH recommends a peak of 170-400 ng/ml,  which corresponds to a PR of 1.6-2.3.

The PR has to be interpreted in the context of the timing of the last dose. Note that routine Rivaroxaban monitoring is not recommended. Contact a Haematologist for advice in interpretation of result if required.

Apixaban

The reference range of apixaban is not known. Trough levels of 30-60 ng/mL are expected during lower dose treatment
of apixaban and >100 ng/mL as peak levels during therapy (ISTH SSC Subcommittee on control of anticoagulation,
J Thromb Haemostat epub 23 Feb 2014). A safe residual apixaban level for surgery is presently unknown and no test
has been correlated with bleeding risk (Ward et al, Thrombosis J 2013, 11:27)."

Fondaparinux

The drug level needs to be interpreted in conjunction with timing of the specimen in relation to drug administration and whether this is used as prophylaxis

or therapy. The published levels from Phase III trials, taken 3-4 hours after a dose, are 0.2-0.4 ug/ml for prophylactic use and 0.5-1.5 ug/ml  for therapy.

Turnaround Time:

• Within 2 hours from arrival in the laboratory for inpatient samples.
• Within 24 hours from arrival in the laboratory  for samples from laboratories outside of Auckland Hospital.

Contact Information

For further information contact the Haematology laboratory (Ext 22067) or:

Dr Nicola Eaddy		Ext 22071
Dr Peter Bradbeer		Ext 22062
Dr Anna Ruskova		Ext 22137

Last updated at 15:21:03 14/11/2023