TNF drug levels & Anti-TNF drug neutralising antibodies (Infliximab, Adalimumab)
A significant proportion of patients treated with anti-TNF therapy are primary non-responders and require dose-or dose frequency adjustments. The lack of response to treatment has also been attributed to immunogenicity and the development of anti-drug neutralising antibodies.
Studies have shown that response rates increase with infliximab trough concentration and serum drug levels at 4 weeks post-infusion in some patients are positively correlated with duration of response. However the probability of an infection increases with the number of anti-TNF infusions. Anti-TNF drugs can therefore be considered to have a narrow therapeutic index and drug monitoring based on serum trough levels together with monitoring for anti-drug antibodies may improve clinical treatment decisions.
Drug levels and free anti-drug antibodies to adalimumab and infliximab are measured by chemiluminescence (Theradiag).
An in-house ELISA assay is used to measure serum trough drug levels. Neutralising antibodies are measured by luminescence with a TNF sensitive transfected cell line.
For the monitoring of patients treated with Infliximab or Adalimumab. (Please note the free anti-drug antibody assays are not drug tolerant and will only be measured when drug levels are low).
Target trough levels for anti-TNF differ based on disease type, sampling time point (induction vs maintenance) and the target therapeutic outcome (e.g. clinical response vs endoscopic remission).
Perform venesection BEFORE next drug infusion
Awaiting UKAS Accreditation.
This test is not currently accredited
Record last updated
September 3, 2025
Sample Container
5ml RST Vacutainers (Rust 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