Figure 2.

Intermediate anti-infliximab antibodies levels (3.0–9.9 µg/ml) quantified by QB rapid test, In-House, Theradiag, and Immundiagnostik assays in the presence of exogenous infliximab. The horizontal dotted line is the lower limit for positive levels of ATIs using the clinical cutoffs (1.7 μg/ml for QB rapid test, In-House and Theradiag, and 10 AU/ml for Immundiagnostik). The vertical dotted line is the upper limit of the therapeutic range of infliximab concentrations (0–100 μg/ml). QB rapid test indicated invalid values in some samples in the 100 µg/ml IFX concentrations.

ATIs anti-infliximab antibodies; IFX, infliximab; QB, Quantum Blue.