Comparison of five diagnostic methods for Helicobacter pylori

Abstract

Background and objectives: Invasive and non-invasive techniques are used to diagnose H. pylori infection. Some factors influence the choice of a diagnostic test, such as the sensitivity and specificity of the tests, the clinical circumstances and the cost-effectiveness of the testing strategy. The aim of this study was to reveal the relationship between different H. pylori infection diagnosis methods, and clarify the application scope of each diagnosis method.

Materials and methods: patients were included in the study, and specimens including biopsies, blood and stool were taken. Biopsies were evaluated by hematoxylin and eosin, and Giemsa staining. A sequence of 294 bp in the ureC (glmM) gene was amplified. The rapid urease test (RUT) was performed using a non-commercial validated test. Stool samples were analyzed using a polyclonal ELISA stool antigen test. A serological assay for IgG antibodies was performed by a commercial Helicobacter pylori IgG ELISA kit.

Results: According to the predefined criteria, a total of 46 (50.5%) patients tested were positive by at least 2 of the 3 biopsy-based methods. The best sensitivity (95.6%) belonged to histology and RUT. The sensitivities of other tests including PCR, serology and stool antigen test were 93.5%, 91.3% and 73.9%, respectively. RUT showed the best specificity (100%), and the specificities of the other tests, including PCR, stool antigen test, histology and serology, were 95.6%, 86.7%, 77.8% and 55.6%, respectively.

Conclusion: In view of the better results obtained for invasive vs non-invasive tests, for a more accurate diagnosis, it is advisable not to solely rely on non-invasive methods of H. Pylori diagnosis.

Keywords: ELISA; Helicobacter pylori; Histopathology; PCR; RUT; Stool antigen test.

Fig. 1

PCR products for H. pylori with glmM gene based primers. Lane 1, ladder; Lane 2, positive control; Lane 3, negative control; Lane 4-10, Patients biopsy samples.