Referred to Biochemical Sciences, Synnovis Hub, London SE1 8NZ|
Alternative names, keywords |
Anti-TNF alpha drugs, Anti-Infliximab antibody, Remsima, Flixabi, Inflectra. |
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Samples required |
● Clotted blood (gold cap, 5 mL tube). Smaller tubes are available for paediatric samples. Trough level recommended (immediately before the next dose is due). For prompt referral of sample please specify which drug patient is on. |
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Test indications |
Monitoring infliximab treatment: primary treatment failure (non-response), secondary loss of response, prediction of infusion reactions, adherence to therapy, reintroduction after drug interruption. |
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Test information |
Interpretation requires full clinical details: drug dosage/ frequency, previous exposure to other biologics, time of sampling, duration of therapy and clinical assessment. |
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Reference range |
Suggested target drug concentrations for intravenous infliximab in the treatment of IBD: Induction/post-induction: Week 2 to target: 20 - 25 ug/mL Maintenance to target: 5 - 10 ug/mL Target concentrations are based on Cheifetz* et al. (2021) and apply only to intravenous infliximab in inflammatory bowel disease. Therapeutic levels for subcutaneous infliximab have not been established. All TDM thresholds are estimates based on population data. Results should always be interpreted in the context of the clinical situation. *Cheifetz et al, Am J Gastroenterol 2021;116:2014-2025.
In the presence of drug levels greater than 2.5 µg/mL, free anti-drug antibody cannot be detected and therefore its measurement is not indicated. Anti-infliximab antibody: 0 - 10 ng/mL |
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Turnaround time |
Referral lab quotes turnaround time of 2 weeks, however additional time must be allowed for packing, dispatch and delivery of sample, and return and processing of results. |
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Enquiries |
Biochemistry (Referrals) |