Therapeutic drug monitoring is becoming increasingly important in clinical decision making in children with inflammatory bowel disease (IBD). However, ELISA assays do not allow results to be provided in real-time. We sought to compare two point-of-care (POC) devices for quantification of serum infliximab concentration with two validated ELISA assays in children with IBD.
We studied 32 serum samples from 19 children with IBD treated with infliximab. Serum samples were collected immediately before drug infusion (trough level). Infliximab was measured using two POC infliximab assays, Quantum Blue (POC IFX/QB) and Rida Quick (POC IFX/RQ), and two ELISA assays: Lisa-Tracker (used as primary reference), and Promonitor (used as second control). Intraclass correlation coefficient (ICC) was assessed for quantitative comparison. Qualitative analysis was also performed to evaluate whether POC assays would correctly classify infliximab serum according to a target window (between 3 μg/ml and 7 μg/ml).
ICC was 0.82 and 0.87 for POC IFX/QB and POC IFX/RQ with the primary reference ELISA assay, respectively; ICC between the two ELISA assays was 0.87. Classification of results according to therapeutic intervals showed good agreement between pairs of assays, with kappa of 0.67 and 0.80 for POC IFX/QB and POC IFX/RQ, respectively, with reference ELISA, and 0.81 between the two ELISAs. Accuracy of POC assays was better for drug levels <3 μg/ml.
POC infliximab assays showed good agreement with traditional ELISA assays. POC devices may represent a viable option for real-time therapeutic drug monitoring in children treated with infliximab.
*PhD School in Science of Reproduction and Development, University of Trieste, Trieste, Italy.
†Experimental and Clinical Pharmacology Unit, Centro di Riferimento Oncologico di Aviano (CRO) IRCCS, Aviano, Italy.
‡Institute for Maternal and Child Health IRCCS “Burlo Garofolo”, Trieste, Italy.
§Department of Medical and Biological Sciences, University of Udine, Udine, Italy.
||Pediatrics Unit, Ca’ Foncello Hospital, Treviso, Italy.
¶Department of Laboratory Medicine, Institute of Clinical Pathology, University Hospital of Udine, Udine, Italy.
#Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy.
**Department of Life Sciences, University of Trieste, Trieste, Italy.
Address correspondence and reprint requests to Samuele Naviglio, MD, PhD, Institute for Maternal and Child Health - IRCCS “Burlo Garofolo”, Via dell’Istria 65/1, 34137, Trieste, Italy (e-mail: email@example.com).
Received 30 January, 2019
Accepted 13 May, 2019
Conflicts of Interest and Source of Funding: All Authors declare no conflict of interests. No external funding was received for this work; the work was funded by the Institute for Maternal and Child Health IRCCS Burlo Garofolo, research project RC 17/1.