In clinical decision-making for children with inflammatory bowel disease (IBD), therapeutic medication monitoring has become increasingly crucial. However, the techniques of enzyme-linked immunosorbent assay (ELISA) techniques did not offer real-time findings. For a study, researchers compared two point-of-care (POC) devices for measuring blood infliximab concentrations with two validated ELISA assays in children with IBD. Researchers examined 32 blood samples from 19 children with IBD using infliximab. Serum samples were taken shortly before the medication infusion (trough level). Infliximab levels were determined using two POC infliximab tests, Quantum Blue (POC IFX/QB) and Rida Quick (POC IFX/RQ), as well as two ELISA assays, Lisa-Tracker (primary reference) and Promonitor (used as second control). For quantitative comparison, the intraclass correlation coefficient (ICC) was calculated. A qualitative investigation was also conducted to determine if POC tests accurately classified infliximab serum within a predefined window (between 3 and 7 g/mL).
The ICC with the principal reference ELISA assay was 0.82 and 0.87 for POC IFX/QB and POC IFX/RQ, respectively; the ICC between the two ELISA assays was 0.87. The data classification according to treatment intervals revealed good agreement across test pairs, with kappa values of 0.67 and 0.80 for POC IFX/QB and POC IFX/RQ, respectively, with reference ELISA, and 0.81 for the two ELISAs. POC tests performed better at drug concentrations of less than 3 μg/mL.
POC infliximab tests were shown to be very accurate compared to standard ELISA assays. POC devices might be a feasible solution for real-time therapeutic drug monitoring in children using infliximab.