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P513 Performance of a rapid test for adalimumab monitoring vs. conventional ELISA in a routine laboratory setting

T. Van Stappen*1, B. H. Roovers2, F. van Deurzen2, A. J. van Vuuren2

1R-Biopharm AG, Clinical Diagnostics, Darmstadt, Germany, 2Erasmus MC, Gastroenterology and Hepatology Diagnostic Laboratory, Rotterdam, The Netherlands

Background

Therapeutic drug monitoring of adalimumab is useful to optimise the treatment of patients with inflammatory diseases, such as inflammatory bowel disease. A recent study reported the potential benefit of rapid testing for adalimumab concentrations as early as Week 4, using the RIDA®QUICK ADM Monitoring, to help predict later anti-drug antibody development and the need for dose intensification.1 Nevertheless, data regarding the performance of a rapid test in a routine clinical laboratory are scarce. In this study, we therefore aimed to evaluate and confirm the performance of the RIDA®QUICK ADM Monitoring in an routine diagnostics laboratory, the Gastroenterology and Hepatology Diagnostic Laboratory (Erasmus MC, Rotterdam, the Netherlands).

Methods

A total of 56 anonymized patient samples were analysed using the RIDA®QUICK ADM Monitoring (R-Biopharm AG, Darmstadt, Germany) and results compared with a conventional ELISA, the apDia Adalimumab ELISA (apDia, Turnhout), also distributed by R-Biopharm as RIDASCREEN® ADM Monitoring. Six quality control samples, with a concentration within the assay analytical range, were used to verify the assay performance.

Results

The RIDA®QUICK ADM Monitoring was shown to correlate very well with the apDia Adalimumab ELISA (Pearson r coefficient of 0.91). The absolute bias between the two methods was 1.6 ± 2.2 µg/ml (Figure 1).

Figure 1. Bland-Altman plot showing the absolute difference between the apDia Adalimumab ELISA and the RIDA®QUICK ADM Monitoring vs. the average of the two methods. The average bias was 1.6 ± 2.2 µg/ml (n = 56).

Linear regression analysis showed no systemic or proportional bias between the RIDA®QUICK ADM Monitoring and apDia Adalimumab ELISA (y = 0.89 (±0.06)x – 0.48 (±0.69); y = RIDA®QUICK ADM Monitoring; x = apDia Adalimumab ELISA).

Conclusion

In this study, we confirmed the performance of the RIDA®QUICK ADM Monitoring in a routine diagnostics laboratory, revealing a very good agreement with a conventional ELISA technique. The RIDA®QUICK ADM Monitoring allows to measure one sample at a time and has a turn-around time of only 20 min.

Reference

1. Verstockt B, Moors G, Bian S, et al. Influence of early adalimumab serum levels on immunogenicity and long-term outcome of anti-TNF naive Crohn’s disease patients: the usefulness of rapid testing. Aliment Pharmacol Ther, 2018;48:731–739.