Department of Paediatric Gastroenterology, Wilhelmina Children's Hospital, Utrecht.
Department of Paediatric Gastroenterology, Erasmus MC-Sophia Children's Hospital, Rotterdam.
J Pediatr Gastroenterol Nutr. 2021 Jan 1;72(1):56-60. doi: 10.1097/MPG.0000000000002906.
Blood to measure infliximab (IFX) levels is typically obtained with venipuncture. Dried blood sampling (DBS), using capillary blood obtained from a finger prick, would be an alternative to measure IFX blood levels while being more patient friendly. The aim of this study is to compare IFX blood level measured by venipuncture versus DBS in patients with paediatric inflammatory bowel disease (PIBD) to assure accuracy.
A prospective clinical pilot study was performed in patients with PIBD. Before IFX infusion, blood was collected simultaneously through venipuncture and DBS from a finger prick, using Mitratips (Neoteryx). All IFX concentrations were measured by an enzyme-linked immunosorbent assay. The Bland-Altman analysis was used to measure limits of agreement. The interrater reliability was measured with the interclass correlation coefficient and Cohen kappa. To calculate Cohen kappa, IFX levels were categorized into 3 groups; low <5 μg/mL, adequate 5 to 10 μg/mL, and high >10 μg/mL.
Twenty patients were included. Median age was 12.1 year (interquartile range 8-16 year). The mean difference between the 2 methods was -0.14 as calculated with Bland-Altman plot. The limits of agreement were between -1.39 and 1.12. The interclass correlation coefficient was with 0.998 excellent. The Cohen kappa between 3 IFX level categories was strong K = 0.911 (P = 0.0001). There was a strong correlation between venous IFX serum levels and DBS (r = 0.991, P = 0.0001) in the included patients.
This is the first study in patients with PIBD to show that bloodspot technology is a patient friendly alternative method to measure IFX blood levels in PIBD.
通常通过静脉穿刺采集血液来测量英夫利昔单抗（IFX）水平。使用手指刺破获得的毛细血管血进行干血斑采样（DBS），可以替代测量 IFX 血药浓度，同时更便于患者接受。本研究旨在通过比较儿科炎症性肠病（PIBD）患者静脉穿刺与 DBS 采血测量 IFX 血药浓度的结果，确保其准确性。
对 PIBD 患者进行前瞻性临床试点研究。在 IFX 输注前，通过 Mitratips（Neoteryx）同时从手指刺采血样进行静脉穿刺和 DBS 采集。所有 IFX 浓度均采用酶联免疫吸附试验进行测量。采用 Bland-Altman 分析来测量一致性界限。采用组内相关系数和 Cohen kappa 来测量组间信度。为了计算 Cohen kappa，将 IFX 水平分为 3 组：低 <5μg/mL、中 5 至 10μg/mL、高 >10μg/mL。
共纳入 20 例患者。中位年龄为 12.1 岁（四分位间距 8-16 岁）。Bland-Altman 图计算的 2 种方法之间的平均差值为-0.14。一致性界限在-1.39 和 1.12 之间。组内相关系数为 0.998，极好。3 个 IFX 水平分类之间的 Cohen kappa 值为强 K=0.911（P=0.0001）。纳入患者中静脉 IFX 血清水平与 DBS 之间存在很强的相关性（r=0.991，P=0.0001）。
这是第一项在 PIBD 患者中开展的研究，表明血斑技术是一种便于患者接受的替代方法，可用于测量 PIBD 中的 IFX 血药浓度。
