Diagnosis of helicobacter pylori infection by ELISA stool antigen and comparison with the other diagnostic methods

Purpose: The object of this study is to design a simple and sensitive enzyme immune assay method for detecting Helicobacter pylori antigens in stool. Materials/Methods: Stool samples were collected from 116 adults who were undergoing endoscopic examinations and stomach biopsies and for whom histology and rapid urease tests were performed. A monoclonal antibody was used as the capturing antibody and a polyclonal antibody of rabbit origin conjugated with a peroxidase enzyme as the tracer. Results: In the histology and rapid urease tests, 21 of the 116 patients (18.1%) had positive results. H. pylori antigens were detected by the designed method in 19 of 21 cases (a sensitivity of 91%). Also, all of the 95 cases with negative results in the histology and rapid urease tests were negative for the stool antigen test (a specificity of 100%). For comparison, the sensitivity and specificity of the rapid immuno-chromatography test by the Certest Company were 95% and 99%, respectively. The total correlations between the results of the designed ELISA test with the results of the rapid test and the ELISA test of the Astra Company were 96% and 80%, respectively. Conclusions: This non-invasive and economical method for the detection of H. pylori antigens in stool can be considered as an alternative test that provides comparable reliability and validity to the histology and rapid urease tests for the detection of H. pylori infections.