Ustekinumab Free Anti-drug Antibody ELISA (IDKmonitor®)


Ustekinumab is a fully humanised IgG1 therapeutic monoclonal antibody used for the treatment of Crohn’s disease, ulcerative colitis, plaque psoriasis and psoriatic arthritis. It targets cytokines IL-12 and IL-23 which are involved in immune-mediated inflammatory disorders.

The IDKmonitor Ustekinumab Free Anti-drug Antibody ELISA measures free antibodies against ustekinumab (e.g. STELARA®). This assay enables the reliable determination of free, unbound anti-drug antibodies; therefore it is ideal for therapy monitoring when a measurable ustekinumab concentration is not expected, or the unbound fraction of anti-drug antibodies is required, for example shortly before the next infusion. In combination with the drug level determination, the IDKmonitor® Ustekinumab Free Anti-drug Antibody ELISA supports the monitoring and optimisation of therapy.


  • Supports the investigation of primary non-response and loss of response to ustekinumab

  • Highly sensitive assay that detects free anti-ustekinumab antibodies (those unbound to ustekinumab)

  • May help to predict long term outcome of disease

  • Applicable to both gastroenterology and rheumatology

  • Automatable on ELISA automates (e.g. Dynex D2)