Pathology

Test & Collection Guide

Anti-Xa Assay

Ordering information:

Required information: the anticoagulant type ( ie. unfractionated Heparin, Clexane, Fragmin, Rivaroxaban, Apixaban or Fondaparinux ) being monitored MUST be indicated on the request.

This information is required to select the correct assay.

Alternate names:

10a, Apixaban level, Clexane level, F10a, Fondaparinux level, Fragmin level, Rivaroxaban level, Unfractionated heparin level

Laboratory:

Coagulation

Test Code:

10A: Clexane, 10AH:Plasma Heparin, APIX: Apixaban, RIVX: Rivaroxaban, FONX: Fondaparinux

Specimen types:

Plasma

Container types:

Sodium Citrate

Collection Instructions:

Sample haemolysis may make this test unreportable
Samples found to have clots cannot be tested

Excerise great care in collection and handling of plasma to avoid the release of platelet factor 4 (PF4) which is a potent inhibitor of heparin.

Sampling times

Clexane 3 hr post injection.

Fragmin 3 - 4 hr post injection.

3.5 mL Sodium Citrate tube filled to label marker, mixed by inversion and sent to laboratory immediately.

Do not use 1 ml citrate tubes.

Minimum Adult Volume:

4 mL

Notes:

If testing is delayed by more than 4 hours: spin separate and freeze plasma (plasma should be double spun)

Specimen rejection: specimens that are under or over filled , specimens that do not meet identification requirements.

Frequency:

Daily

Result Turnaround Time:

2 days

Reference Interval:

Therapeutic range can depend on treatment regime and be influenced by renal function and weight.

Contact the Haematologist / Registrar for advice.

Laboratory Use Only

Storage Instructions:

Used for monitoring therapeutic doses of LMW heparin ( Clexane and Fragmin). It is not required for prophylactic doses of unfractionated heparin (use APTT).

Centrifuge and separate plasma within 1 hour of collection.