Haematology

Preferred Sample Type

Anti-Xa Assay

Anti-Xa Assay

Specimen Volume

3.5 mL (Vacuette tubes) or 2.7mL (BD Vacutainer tubes)

Specimen Transport

Standard transport to laboratory - State for the attention of Special Coagulation on request form

Sample Preparation

Samples must be filled to the black fill line (Vacuette tubes) or the frosted line (BD Vacutainer tubes) indicated on the sample tube. Any sample filled above or below this level will be rejected and a repeat sample will be required

Turnaround Time

7 days (Unless urgent by prior arrangement with laboratory)

Sample Processing In Laboratory

Sample should be centrifuged

Sample Stability

12 hours from venepuncture (ideally received no later than 4 hours after collection)

General Information

Test Availability:

Queen Elizabeth and Heartlands sites: LMWH

Queen Elizabeth site only: UFH, Apixaban, Rivaroxaban, Fondaparinux

Heartlands site only: Edoxaban

Samples received at each site will be sent on to the appropriate laboratory for testing.

Note: For external requests please click Here for Coagulation Disorders request form. Please complete all information fully.

For urgent special coagulation assay information click Here

Samples that meet the following criteria will not be processed:

  • Haemolysed, clotted, underfilled or overfilled samples.
  • Samples >12 hours old from the time of collection.
  • Samples received from other hospital laboratories that have been frozen and thawed.
  • Samples which fail the minimum data set.

Assay Limitations:

  • For accurate results samples should be collected 3-4 hours post dose, when the concentration in the blood is expected to be at peak level.
  • Random and trough anti-Xa tests may also be requested when there are concerns that the anticoagulant may be accumulating e.g. in renal failure.
  • If heparin is being given by continuous venous infusion, samples can be taken at any time but they must be taken from the other arm.

Notes

Please state anticoagulant on request form e.g. LMWH, UFH, Apixaban, Rivaroxaban, Fondaparinux or Edoxaban. Samples must be collected 4 hours post dose.

LMWH: Samples should be taken 4 hours after subcutaneous injection, once steady state has been achieved after administration of at least three doses.

Reference Range

LMWH:

Prophylactic Reference Range 0.1-0.3 IU/mL

Therapeutic Range 0.5-1.0 IU/mL

Therapeutic range for mechanical heart valve during pregnancy 1.0-1.4 IU/mL

Rivaroxaban:

Stroke prevention in NVAF 20mg OD 184-343ng/mL[1]

Treatment of PE/DVT 20mg OD 189-419ng/mL[1]

Treatment of PE/DVT 10mg OD 7-273ng/mL[2]

Treatment of ACS 2.5mg OD 13-123ng/mL[2]

Apixaban:

Stroke prevention in NVAF 5mg BD 91-321ng/mL[1]

Stroke prevention in NVAF 2.5mg BD 69-221ng/mL[2]

Treatment of PE/DVT 10mg BD 111-572ng/mL[2]

Treatment of PE/DVT 5mg BD 59-302ng/mL[1]

Treatment of PE/DVT 2.5mg BD 30-153ng/mL[2]

Fondaparinux:

2.5mg OD 0.39-0.50ug/mL[1]

7.5mg OD 1.20-1.26ug/ml[1]

Edoxaban:

Stroke prevention in NVAF 60mg OD 125-245ng/mL[1]

Treatment of PE/DVT 60mg OD 149-317ng/mL[1]

Stroke prevention in NVAF 30mg OD 55-120ng/mL[2]

Treatment of PE/DVT 30mg OD 99-125ng/mL[2]

 

[1] Measurement of heparin, direct oral anti-coagulants and other non-coumarin anti-coagulants and their effects on haemostasis assays: A British Society for Haematology Guideline, Baker et al, Brit J Haematol, 2024

[2] Update of the International Council for Standardization in Haematology Recommendations for Laboratory Measurement of Direct Oral Anticoagulant, Douxfils et al, Thromb Haemost, 2021

Specifications

  • EQA Status: NEQAS / ECAT
  • EQAS Scheme: Yes

Creation Date

Monday, 08 August 2011

Modification Date

Thursday, 13 February 2025

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Protection of Personal Information – Pathology Laboratories Services comply with the Trust Data Protection Policy and have procedures in place to allow the Directorate and it’s employees to comply with the Data Protection Act 1998 and associated best practice and guidance.

The laboratories at Queen Elizabeth Hospital, Heartlands Hospital, Good Hope Hospital and Solihull Hospital form part of the services provided by University Hospitals Birmingham and are UKAS (United Kingdom Accreditation Service) accredited to the ISO 15189:2022 standard. For a list of accredited tests and other information please visit the UKAS website using the following link: https://www.ukas.com/find-an-organisation/ 

  • Molecular Pathology is a UKAS accredited medical laboratory No. 8759
  • Biochemistry is a UKAS accredited medical laboratory No. 8910
  • Haematology and Transfusion is a UKAS accredited medical laboratory No. 8784
  • Clinical Microbiology is a UKAS accredited medical laboratory No. 8760
  • Cellular Pathology is a UKAS accredited medical laboratory No. 10141
  • United Kingdom Health Security Agency laboratory is a UKAS accredited medical laboratory No.8213

Tests not appearing on the UKAS Schedule of Accreditation currently remain outside of our scope of accreditation. However, these tests have been validated to the same high standard as accredited tests and are performed by the same trained and competent staff.

For further test information, please visit the test database: https://qehbpathology.uk/test-database 

For further information contact Louise Fallon, Quality Manager, 0121 371 5962/ 0121 424 1235