Demonstrating some assets of the apDia (Ridascreen®) ELISA kit.
Therapeutic drug monitoring of tumor necrosis factor inhibitors, such as adalimumab, is increasingly being carried out for the management of autoimmune diseases.
However, there can be significant variation in drug and antibody concentrations obtained by different assay methods. The aim of this study was to compare the performance of four ELISA kits for measuring adalimumab and anti-adalimumab antibodies.
Dilutions of adalimumab or anti-adalimumab spiked sera were assessed for recovery rate and precision using the following four kits: LISA-Tracker (Theradiag, Croissy- Beaubourg, France), Promonitor (Grifols, Barcelona, Spain), Ridascreen (R-Biopharm, Darmstadt, Germany), and Shikari (Matriks Biotek, Gölbaşi/Ankara Turkey). Interference samples were also assessed.
At the therapeutic concentration, adalimumab detection was comparable among the four ELISA kits. Lisa-Tracker and Shikari kits produced low-range false positive results in normal sera. Infliximab and etanercept caused false positives in Lisa-Tracker and Shikari kits.
Anti-adalimumab antibody ELISA kits performed differently with spiked samples due to different measuring units and ranges. Ridascreen and Shikari kits were dose-responsive across the entire standard curve and correlated well with each other (r2 = 0.997). Crossreactivity was observed in rheumatoid factor positive sera tested on the Promonitor antiadalimumab kit.
All adalimumab kits tested were dose-responsive within the therapeutic range
and correlated well. The significance of observed low-range false positives and crossreactivity with infliximab in LISA-Tracker and Shikari kits is dependent on the indications received for testing in the laboratory. Anti-adalimumab ELISA kits produced varied results for spiked sera; however, they showed good precision. Inter-kit variability suggested that anti-adalimumab levels should be compared only when using the same method.
Reference: Sam MJ, Connor SJ, Sang Ng WW, Mei-Ling Toong C. A Comparative Evaluation of Four Commercially Available ELISA Kits for Measuring Adalimumab and Anti-adalimumab Antibodies. Ther Drug Monit. 2020 Sep 15.