Background: Noninvasive diagnostic tests are useful as screening tools for Helicobacter pylori infection in pediatric populations. The aim of this study was to evaluate performance of the immunoblot assay, Helico Blot 2.1, for the diagnosis of H. pylori infection in symptomatic children.
Materials and methods: Immunoblot assay was used for detection of IgG antibodies to specific H. pylori proteins and to a recombinant H. pylori antigen, CIM marker. The study was performed on sera collected from 134 symptomatic, untreated children (mean age, 9.1 +/- 3.2 years; range, 1-14 years). H. pylori infection status was determined by culture, histology and rapid urease test.
Results: Immunoblot assay yielded a positive result in 71 of the 72 infected patients (sensitivity 98.6%) and in eight of the 62 noninfected ones (specificity 87.1%). The predictive values for a positive and a negative result were 89.9% and 98.2%, respectively. The performance of the CIM band alone, as a marker for H. pylori infection status, was also evaluated. This band was present on the blot of 71 infected patients and on four of the 62 H. pylori-negative patients. The sensitivity, specificity, PPV and NPV of the CIM antigen were 98.6%, 93.5%, 94.7% and 98.3%, respectively.
Conclusions: The immunoblot assay Helico Blot 2.1 is a suitable noninvasive test for the serodiagnosis of H. pylori infection in children. The good level of performance demonstrated by the novel recombinant antigen CIM suggests it may be a useful contribution to the qualitative and quantitative performance of the Helico Blot 2.1 in pediatric populations.