The measurement of Etanercept is a useful tool in managing patients who fail to respond (primary failure) or who go on to lose response (secondary failure) to treatment. Monitoring drug levels allows for a personalised approach to drug optimisation by appropriate dose escalation/de-escalation or drug switching/withdrawal.

Measured as part of a profile including anti-Etanercept antibodies.

This test is not currently included in the laboratory's UKAS scope of accreditation to ISO15189:2012.
Clinical details: 
Etanercept is a recombinant human fusion protein of the extracellular ligand-binding portion of human tumour necrosis factor receptor, linked to the Fc portion of human IgG1. Etanercept acts as a decoy receptor for tumour necrosis factor alpha (TNFα). Etanercept is licensed for use in Rheumatology (rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, juvenile idiopathic arthritis) and Dermatology (sever plaque psoriasis). Due to its high cost, Etanercept is only indicated in patients with severe disease which is refractory to conventional therapeutic approaches.
Reference range: 

Test interpretation requires full clinical information: drug dosage/frequency, previous exposure to other biologics, time of sampling, duration of therapy and clinical assessment. Therapeutic range for Etenercept is yet to be defined but literature review of studies using our kit suggests Etanercept concentrations >3.1 μg/mL at 3 months predict response at 6 months.

Sample type and Volume required: 
Serum (SST tube or plain) sample is preferred. Plasma (Lithium heparin, citrate or EDTA) is also acceptable. Minimum 300μL serum or plasma required for both drug and anti-drug antibody analysis.
Turnaround time: 
Please contact the laboratory to discuss.
Special sample instructions: 

Collect blood into a serum separation (SST™) or plain tube, preferably shortly before drug administration (trough levels). Centrifuge sample at 3000 rpm for 10 minutes, aliquot serum or plasma and keep in fridge until transport. If transport is going to be delayed by > 5 days, freeze at -20°C and send by first class post at a later date.

Storage and transport: 
Post the sample to Viapath Central Specimen Reception by first class post (see request form for full address).
Reference Chemistry Laboratory at St Thomas'
0207 188 1264
4th floor, North Wing
St Thomas' Hospital
Westminster Bridge Road
London SE1 7EH
For clinical advice or interpretation of results, please contact the laboratory in the first instance.

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Last updated: 12/10/2022