T-cell activation markers
This is a flow cytometric assay used to quantify the percentage of T- cells (CD3+/CD4+ and CD3+/CD8+ cells) expressing the activation markers CD25 and HLA-DR. This test is currently only available to the National HTLV-1 service.
HTLV-1 is a CD4 tropic retrovirus that is asymptomatic in around 90% of patients. In the UK an estimated 22,000 people are infected. Around 2-5% of HTLV-1 infected patients will have malignant transformation to adult T cell leukaemia/lymphoma (ATLL) and up to 3% of infected patients develop a progressive disease of the nervous system (HAM/TSP, HTLV-1 associated myelopathy/tropical spastic paraparesis).
Serial monitoring of the CD4+CD25+ population in HTLV-1 patients may aid in predicting disease progression.
Monitoring HTLV-1 infection
| T cell activation subsets | Ranges (%) |
| CD3+CD4+CD25+ | 15.7- 34.9 |
| CD3+CD4+HLADR+ | 4.2 – 13.9 |
| CD3+CD8+CD25+ | 4.6 – 10.9 |
| CD3+CD8+HLADR+ | 5.7 – 38.2 |
Ranges validated in house
Do not separate or refrigerate, must be processed within 48 hours
Record last updated
August 27, 2025
Sample Container
4ml EDTA Vacutainers (Lavender top)
Search test database
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