Evaluation of a novel monoclonal enzyme immunoassay for detection of Helicobacter pylori antigen in stool from children

Abstract

Background: Reliable non-invasive methods for detection of Helicobacter pylori infection are required to investigate the incidence, transmission, and clearance of infection in childhood. Aim: To evaluate a new monoclonal enzyme immunoassay (EIA) (FemtoLab H pylori Cnx) for detection of H pylori antigen in stool in a large cohort of children compared with invasive diagnostic methods and the 13 C urea breath test. Patients and methods: A total of 302 symptomatic previously untreated children (aged 0.5-18.7 years; 148 girls) were recruited at three centres. H pylori status was defined by results of culture, histology, the rapid urease test, and the 13 C urea breath test. Stool samples were investigated locally by the EIA using two different production lots. According to the manufacturer's recommendations, an optical density (OD) of 0.150 was used as a cut off value. Results: OD values clearly differentiated between the 92 H pylori infected and the 210 non-infected children (median (5th-95th percentiles) 2.729 (0.232->4.000) v 0.021 (0.009-0.075)). Only two false positive and two false negative results occurred, giving a sensitivity, specificity, positive predictive value, and negative predictive value of 98%, 99%, 98%, and 99%, respectively. No significant relation was found between age and OD values in infected or non-infected children. Conclusions: The monoclonal stool antigen EIA was excellent in diagnosing H pylori infection in symptomatic children. Accuracy was independent of the laboratory, production lot used, or the child's age. Because only 18/116 children <6 years of age were infected with H pylori, further validation of the test is needed in young infected children.

Sensitivity of a Novel Stool Antigen Test for Detection of Helicobacter pylori in Adult Outpatients before and after Eradication Therapy

“…The authors performed the test with 79 children, 39 of whom were considered to be H. pylori positive (according to positive results from UBT and serology). The test yielded a sensitivity value of 98%, which is the same result we have received in a recently published European multicenter study involving 302 symptomatic children (9). In the latter study, these excellent results were obtained in spite of the fact that the test was performed in three different laboratories using different production lots.…”

“…The FemtoLab H. pylori test is a novel EIA using a monoclonal antibody to detect H. pylori antigen in feces. Published data concerning the evaluation of this stool antigen test are from studies whose scope was limited either to pediatric patients (9,13) or to adult patients recruited in a tertiary center (12). In the study of adult patients, the monoclonal stool EIA was evaluated 4 to 6 weeks after eradication therapy but not prior to therapy and the results were compared with those obtained with the UBT.…”

“…Patients with a positive RUT result within less than 20 min of administration of the test qualified for standard Italian triple therapy (2 ϫ 400 mg of metronidazole, 2 ϫ 500 mg of clarithromycin, and 2 ϫ 20 mg of esomeprazole daily for 7 days). The UBT was also performed with all patients after endoscopy in accordance with a validated protocol (9). Patients drank 150 ml of a citric acid solution before the first two breath samples were obtained.…”

Helicobacter pylori and recurrent abdominal pain in children: Is there any relation?

“…To detect H. pylori, 14 C labeled urea supplied in a capsule is swallowed by the patient. If gastric urease synthesized by H. pylori is present, urea is split to form CO 2 and NH 3.…”

Improved Performance of a Rapid Office-Based Stool Test for Detection of Helicobacter pylori in Children before and after Therapy

“…Lack of accuracy is obviously related to intertest variability (19). In contrast, EIA based on monoclonal antibodies showed consistently excellent results, with very high sensitivity and specificity in both children and adults (15,21).A meta-analysis with head-to-head comparison has judged the monoclonal EIA superior to the polyclonal EIA (8).Recently, we reported on the performance of a one-step monoclonal chromatographic immunoassay for detection of H. pylori antigen in stool samples from symptomatic children compared to the results of a well-established monoclonal EIA using the same antigen, namely, the catalase of H. pylori (22). Evaluation against biopsy specimen-based diagnostic methods showed a moderate sensitivity but a good specificity.…”