Factor assays II, V, VII, VIII, IX, X, XI, XII, XIII, collagen binding assay
Factor assays can be performed where a coagulation factor deficiency is suspected in order to identify abnormal levels of specific coagulations factors. Factor assays are performed using methods based upon the PT or APTT, which are specific for factors II, V, VII and X or factors VIII, IX, XI and XII, respectively. Factor XIII is performed by a chromogenic method and FVIII can also be assayed by a chromogenic method as an alternative to the APTT based method.
Abnormally low results may be significant in a bleeding diathesis, although factor XII deficiency is not associated with an increased risk of bleeding.
Factor assays can also be used to monitor known haemophiliacs receiving factor concentrate.
By approval of Consultant Haematologist
Investigation of a suspected coagulation factor deficiency
Family history of haemophilia
Monitoring pre and post factor concentrate administration
Please Note: Samples will be rejected if under/over-filled, clotted or haemolysed
Factor XIII assay is performed by The Royal Free Hospital Laboratory
Adult Reference Range:
Note: The reference ranges for use on patients over the age of 16 years, has been locally verified in accordance with CLSI Guideline EP28-A3c through evaluation on representative normal individuals across the sites to reflect our patient population.
Data sourced via Stago from:
Monagle P. et al. Thromb Haemost 2006; 95: 362-372.
Summerhayes R. et al. J Thromb Haemost, 2007; 5, Supp 2: P-M-105.
Summerhayes R. et al. J Thromb Haemost, 2007; 5, Supp 2: P-S-397.
Paediatric Reference Range
Note: Due to the complexity of collecting blood samples for analysis on normal neonates and paediatric patients, the reference ranges for use on patients up to 16 years of age have been taken from published data, from a research study using comparable methodology and equipment as that currently employed in our organisation. Please contact the laboratory for coagulation paediatric ranges.
Data sourced via Stago from:
Monagle P. et al. Thromb Haemost 2006; 95: 362-372.
Summerhayes R. et al. J Thromb Haemost, 2007; 5, Supp 2: P-M-105.
Summerhayes R. et al. J Thromb Haemost, 2007; 5, Supp 2: P-S-397.
Record last updated
September 3, 2025
Sample Container
2.7 ml Sodium citrate Vacutainers (Light blue top)
Sample Container
1.8ml Sodium Citrate Paediatric Tube (Light blue top)
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Test Results
Yes, we have a Pathology User Guide
Yes. Please email your request to Imperial.nwlpcustomerservice@nhs.net
Results are communicated to clinical staff and are normally not communicated direct to patients either on telephone requests or in written report. If you need to contact us please click here to view the contact details page
Please contact the Customer Service Team Monday to Friday from 8:30am – 6:00pm on 0203 313 5353. Alternatively, see the Pathology User Guide for how to contact the relevant department. If advice is not urgent you can also email your query to Imperial.nwlpcustomerservice@nhs.net
Additional tests may be added by discussion with the relevant laboratory. The time limit for adding additional tests to a sample already received in the laboratory will depend on the type of sample and the department it was sent to.
Information on the repertoire of tests performed by pathology, including reference ranges, turnaround times and specimen requirements, can be found in the test directory.
Phlebotomy services are not managed by NWLP. For further information please see:
Imperial College Healthcare Trust Phlebotomy services
Chelsea and Westminster Hospital NHS Foundation Trust Phlebotomy services
NWLP operates UKAS accredited medical laboratories as per the references below. The current scope of accreditation for all NWLP’s laboratories can be found on the UKAS website.
See the following UKAS ref numbers:
- Clinical Biochemistry Ref: 8673
- Haematology and Blood Transfusion Ref: 8674
- Infection & Immunity Sciences (Including Immunology, Virology, Microbiology and Histocompatibility and Immunogenetics ) Ref: 8659
- Cellular Pathology (Including Histopathology, Cytology and Molecular Pathology) Ref: 9615
If you require copies of our certificate of accreditation and associated documentation please contact Imperial.nwlpcustomerservice@nhs.net.
UKAS requires the laboratories to be accredited for a particular repertoire/scope (ISO15189), any changes or additions to repertoire require assessment by UKAS (extension to scope).
The BD Hospital Tube Guide, BD GP Tube Guide and BD Paediatric Tube Guide provide visual references to the correct tube types and collection instructions.
Home testing
INSTRUCTION SHEET FOR BLOOD SAMPLE COLLECTION
We also have two instruction videos available (one with subtitles and one without) – please click on the links to view the videos on Google.
Our accreditations
Upholding excellence in diagnostic standards
Our laboratories are accredited by the UK Accreditation Service (UKAS) against the international standard ISO15189:2022. UKAS is the accreditation body for the UK that assesses medical laboratories.
Find out more about our accreditations on the UKAS website.
UKAS website