• The technologies described in this briefing are the RIDASCREEN IFX Monitoring and RIDASCREEN Anti‑IFX Antibodies tests. They are used for measuring free infliximab in the body and for measuring antibodies against infliximab, respectively, in serum or plasma samples.

  • The innovative aspect of these tests is that they provide information on individual responses to infliximab with the aim of helping to guide future treatment and dosage.

  • The intended place in therapy would be in addition to standard practice during maintenance therapy for inflammatory bowel diseases, before the next intravenous infusion, in order to guide drug dosage.

  • The main points from the evidence summarised in this briefing are from 5 studies (1 prospective observational cohort and 4 assay correlation studies, n=587 samples). One study found that an infliximab concentration threshold of at least 2.7 micrograms/ml using the RIDASCREEN IFX Monitoring test was associated with mucosal healing in patients with ulcerative colitis. One study reported a coefficient of variations of 5% at both 3 and 7 micrograms/ml using the RIDASCREEN IFX Monitoring test.

  • Key uncertainties around the evidence are that there are few studies that report clinical outcomes.

  • The costs of the RIDASCREEN IFX Monitoring and RIDASCREEN Anti‑IFX Antibodies tests are £795 and £986, respectively, for up to 40 duplicate or 80 singlicate tests (exclusive of VAT). The additional costs compared with standard care may be offset if the test were shown to optimise drug therapy or to improve disease management.