Detection of Helicobacter pylori infection using single serum specimens: Comparison of five commercial serological tests

Background/Aims: Various commercial kits have been developed for serological diagnosis of Helicobacter pylori infection, but data on their diagnostic accuracy and direct comparisons between the tests are often lacking. We evaluated the sensitivity, specificity and relative agreement of three assay kits which have not been evaluated in published studies so far. Material and Methods: We examined a self-contained card-based enzyme immunoassay (ImmunoCardR H. pylori IgG; Meridian Diagnostics, Milano, Italy) a microwell-based enzyme immunoassay (Enzygnost(R) Anti-Helicobacter pylori/IgG; Behringwerke, Marburg, Germany), and an indirect immunofluorescence test (Immunofluoreszenz IgG Test; Bios, Graefelfing, Germany). We also examined a latex agglutination test (PylorisetR Dry; Orion Diagnostica, Espoo, Finland) and a complement fixation test (CFT H. pylori; Institute Virion, Rueschlikon, Switzerland) which have been evaluated by others previously. Sera originated from 110 patients, sent to the outpatient clinic of a large tertiary hospital for gastrointestinal endoscopy. Results: We found that the latex agglutination test, card-based enzyme immunoassay, and microwell-based enzyme immunoassay had overall sensitivities of 74.4% 95.4% and 90.7% and specificities of 94%, 76.1%, and 79.2% respectively. Indirect immunofluorescence test and complement fixation test yielded sensitivities/specificities of 62.8%/86.6%, and 74.4%/77.6% respectively, when compared with gastric biopsy findings. Combining two tests did not increase the diagnostic yield. The relative agreement of the latex test, card-based enzyme immunoassay, microwell-based immunoassay, immunofluorescence test, and complement fixation test was 86.4%, 83.6%, 83.6%, 77.3%, and 76.4%, respectively. Conclusions: We conclude that for serology based on single serum specimens the enzyme immunoassays and the commercial latex test represent helpful noninvasive tools for the diagnosis of Helicobacter pylori infection. Complement fixation test and IIFT might be more suitable for serological tests on multiple serum specimens, e.g. monitoring the effect of antimicrobial eradication therapy.