Background: Helicobacter pylori (H.pylori ) is the key pathogen for gastroduodenal diseases. The clinical
outcome of H.pylori infection is influenced by the presence of strain-specific virulence factors that are usually
detected by the presence of specific anti-H.pylori antibodies in serum. Apart from the detection of these
antibodies by enzyme-linked immunosorbent assay (ELISA), it is desirable to obtain additional information
concerning the presence of certain virulence factors of H.pylori that could be detected by immunoblot analysis.
Objective: the aim of this work was to evaluate if blotting can replace the need for invasive endoscopy for
diagnosis of virulent H.pylori infection , compare between it and ELISA as serodiagnostic test, and to focus on
identifying factors and markers that define high-risk patients in whom H.pylori infection needs to be
Subjects and Methods: 19 dyspeptic patients were subjected to upper gastrointestinal endoscopy to
obtain antral biopsy, direct urease test and culture of biopsy on specific media . Sera were obtained from the
patients for IgG examination by ELISA and western blotting. Results: Western blotting was more
sensitive(100%) than ELISA (sensitivity 81.8%),but specificity was the same for both (87.5%).Only western
blotting was able to detect antibodies to virulence antigens especially cytotoxin associated antigen(CagA) and
vacuolating cytotoxin antigen (VacA).Conclusion : Western blotting is a highly sensitive noninvasive test to
diagnose toxigenic H.pylori infection. So that unnecessary gastroscopy and treatment can be avoided.