Lupus anticoagulant (LA) screen
LA is a group of antibodies found in patients with SLE, as well as other autoimmune disorders and recurrent fetal loss. Although associated with thrombotic events, it may be characterised by a prolonged APTT, due to an in vitro anticoagulant effect (in contrast to the prothrombotic in vivo effect). Screening for lupus anticoagulant is performed as part of the screen for antiphospholipid syndrome and should therefore be performed in conjunction with a cardiolipin antibody test.
Unexplained arterial or venous thrombosis
Venous thromboembolism at a young age (including childhood)
Recurrent venous thromboembolism
Unusual site of thrombosis (eg. mesenteric, renal, portal veins, cerebral venous sinuses)
Thrombosis during pregnancy or puerperium
Recurrent superficial thrombophlebitis
Arterial thrombosis at a young age (abruptio placentae, pre-term delivery)
Neonatal purpura fulminars or massive thrombosis in newborn
Special handling: avoid prolonged stasis during venepuncture.
Sample must be received by lab within 2 hours of collection. Please note: samples will be rejected if underfilled, clotted or haemolysed, or if they come from patients receiving anticoagulant therapy. Similarly, sampling is inappropriate within 4 weeks post-childbirth, or during an acute phase inflammatory response.
Record last updated
August 21, 2025
Sample Container
2.7 ml Sodium citrate Vacutainers (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