Figure 1

Concordance between serum concentrations of IFX determined by SPR and ELISA. The graph reports the values in 58 patients, i.e. those in which IFX levels were measurable by at least one method. The dotted line indicate the identity line. Bland–Altman analysis, carried out using GraphPad Prism version 7.00 for Windows (GraphPad Software, La Jolla California USA) estimated an “Average Bias” value, i.e. the average of the differences (computed after removal of those out-of-scale for ELISA) of 0.46 ± 1.93 (SD of the Bias), not significantly different from 0.