Performance of a New Rapid Point-of-Care Test for Infliximab Levels in Patients with Inflammatory Bowel Disease: A Comparison to ELISA.

BACKGROUND: Therapeutic drug monitoring of infliximab levels in patients with inflammatory bowel disease (IBD) optimizes patients' treatment. The reference technique is based on enzyme-linked immunosorbent assay (ELISA) although point of care (POC) assays are being developed. AIMS: To assess the performance of a new rapid immunochromatographic POC assay (Promonitor Quick IFX) compared with ELISA technique to measure infliximab levels in patients with IBD. METHODS: A prospective, observational, unicentric study was performed on capillary blood samples from patients with IBD before infliximab infusion (trough levels). Infliximab levels and anti-infliximab antibodies were measured using the ELISA technique (Promonitor IFX) and the POC assay. Correlation between both techniques was assessed by Pearson's coefficient. Quantitative differences were evaluated by Bland-Altman analysis. Samples were stratified according to infliximab therapeutic ranges (< 3 µg/mL, 3-8 µg/mL, and > 8 µg/mL). RESULTS: A total of 135 experimental samples were assessed. Infliximab levels showed a high correlation between POC and ELISA tests (r = 0.84, P < 0.001). The mean difference between tests was 1.46 µg/mL (P < 0.001), being minimal for concentrations < 8 µg/mL. POC and ELISA assays showed an overall concordance of 87.4%. Most samples were in the same therapeutic range, which lead to equivalent therapeutic decisions. POC and ELISA assays detected the presence of anti-infliximab antibodies in 2.2% and 3.7% of the samples, respectively. CONCLUSIONS: POC assay results in blood samples from patients with IBD were comparable to those obtained with the reference ELISA technique. The POC assay could be considered for routine testing based on its ease of use and rapidity.

Corrigendum: Fecal Gluten Peptides Reveal Limitations of Serological Tests and Food Questionnaires for Monitoring Gluten-Free Diet in Celiac Disease Patients.

This corrects the article DOI: 10.1038/ajg.2016.439.

Fecal Gluten Peptides Reveal Limitations of Serological Tests and Food Questionnaires for Monitoring Gluten-Free Diet in Celiac Disease Patients.

OBJECTIVES: Treatment for celiac disease (CD) is a lifelong strict gluten-free diet (GFD). Patients should be followed-up with dietary interviews and serology as CD markers to ensure adherence to the diet. However, none of these methods offer an accurate measure of dietary compliance. Our aim was to evaluate the measurement of gluten immunogenic peptides (GIP) in stools as a marker of GFD adherence in CD patients and compare it with traditional methods of GFD monitoring. METHODS: We performed a prospective, nonrandomized, multicenter study including 188 CD patients on GFD and 84 healthy controls. Subjects were given a dietary questionnaire and fecal GIP quantified by enzyme-linked immunosorbent assay (ELISA). Serological anti-tissue transglutaminase (anti-tTG) IgA and anti-deamidated gliadin peptide (anti-DGP) IgA antibodies were measured simultaneously. RESULTS: Of the 188 celiac patients, 56 (29.8%) had detectable GIP levels in stools. There was significant association between age and GIP in stools that revealed increasing dietary transgressions with advancing age (39.2% in subjects ≥13 years old) and with gender in certain age groups (60% in men ≥13 years old). No association was found between fecal GIP and dietary questionnaire or anti-tTG antibodies. However, association was detected between GIP and anti-DGP antibodies, although 46 of the 53 GIP stool-positive patients were negative for anti-DGP. CONCLUSIONS: Detection of gluten peptides in stools reveals limitations of traditional methods for monitoring GFD in celiac patients. The GIP ELISA enables direct and quantitative assessment of gluten exposure early after ingestion and could aid in the diagnosis and clinical management of nonresponsive CD and refractory CD. Trial registration number NCT02711397.

Incidence, clinical outcomes, and therapeutic approaches of capsule endoscopy-related adverse events in a large study population.

INTRODUCTION: Capsule endoscopy (CE) has become a first-line tool for small bowel (SB) examination. However, adverse events (AEs), such as CE retention or aspiration, may occur. The aims of this study were to evaluate incidence, clinical outcomes and therapeutic approaches of CE-related AEs in the largest series published to date. METHODS: Data from 5428 procedures performed at 12 institutions between August 2001 and January 2012 were retrospectively analyzed. Baseline patient characteristics; procedure; type, localization and symptoms before/after AEs; previous patency tests performed; therapeutic management and patient's outcome were recorded. RESULTS: The overall incidence of CE-related AEs was 1.9%: 2.0% for SB, 0.9% for esophageal and 0.5% for colon CE. The incidence of capsule retention was significantly higher than capsule aspiration (1.87% vs. 0.003%; p < 0.05), in patients suffering from inflammatory bowel disease (IBD) than in obscure GI bleeding (OGIB) (3.3% vs. 1.5%; p < 0.05) and in patients with the combination of nausea/vomiting, abdominal pain and distension. The SB was the most frequent localization of retention (88.2%). The use of patency tests -except for Patency© capsule- before CE was not a good predictor for AEs. Most of the patients with AEs developed no or mild symptoms (97%) and were managed by non-surgical methods (64.4%). CONCLUSIONS: CE-related AEs are uncommon and difficult to predict by imagiological examinations. SB retention, that is usually asymptomatic, is the most frequent AE. In absence of symptoms, non-surgical management of CE-related AEs is recommended.

Complications, limitations, and failures of capsule endoscopy: a review of 733 cases.

BACKGROUND: Although a variety of technical and clinical problems of capsule endoscopy have been reported, their incidence and clinical importance are unknown. The objective was to evaluate the incidence and the type of such events. METHODS: This was a retrospective analysis of 733 consecutive examinations at 4 large referral centers. The main outcome measurements were that the problems were classified as "technical," i.e., related to the functioning of the equipment, and "clinical," i.e., related to patient characteristics. For each type of event, the causes and the impact on the ability to reach a diagnosis were examined. RESULTS: A total of 183 problems were recorded in 174 patients (23.7%): one problem occurred in 165 patients, two in 9 patients. In 8.46% of patients, technical limitations or failures, or clinical complications prevented or hampered diagnosis. Technical problems (e.g., gaps in the recordings, short duration of capsule batteries, failure of downloading) occurred in the early phase of capsule use in 8.6% of examinations and prevented or hampered diagnosis in 2.9%. Clinical problems (difficulty/inability to swallow the capsule, incomplete small-bowel examination) occurred in 16.4% of examinations and hampered or prevented diagnosis in 6.4%. Capsule retention that required surgical or endoscopic retrieval occurred in 1.9% of cases. CONCLUSIONS: Technical problems were rare and hampered or prevented the diagnosis in a very small number of cases. The majority of clinical failures were related to an incomplete small-bowel examination.