Evaluation of two commercial enzyme immunoassays for the diagnosis ofHelicobacter pylori infection

Abstract

Sera from 65 patients with upper gastrointestinal tract symptoms and proven Helicobacter pylori infection, and from 42 negative controls were tested with two commercial EIAs (GAP test, BioRad; and ECP test, Biometra) and two non-commercial EIAs, one performed with whole sonicated cells and the other with acid extract of Helicobacter pylori as antigen. The GAP assay showed a sensitivity of 83.1% and a specificity of 47.6%. The ECP assay showed a sensitivity of 87.7% and a specificity of 61.9%. For both non-commercial EIAs these figures were 87.7% and 88.1%, respectively. Independent of the interpretive criteria established by the manufacturers, receiver operating characteristic curves were plotted for better evaluation of the four methods. Both commercial tests showed a lower probability of yielding a correct diagnosis than the non-commercial tests (p less than 0.05). Although commercial EIAs are convenient for the diagnosis of Helicobacter pylori infection, the accuracy of the two commercial tests evaluated in this study was lower compared to that of the two non-commercial EIAs.

Seroepidemiology of Helicobacter pylori and Hepatitis A Virus and the Mode of Transmission of Infection: A 9-Year Cohort Study in Rural Japan

“…The reference serum sample was diluted serially from 1:2 to 1:16 with PBS (pH, 7.2), and the amount of anti-H. pylori IgG corresponding to a dilution of 1:8 was expressed as an arbitrary index (AI) of 1.0. The cross-reactivity of the antibody in a patient's serum sample with 2 closely related bacterial strains (4 strains of Campylobacter jejuni, 1 strain of Campylobacter ralidis, and 1 strain of Escherichia coli) was examined as described elsewhere [21,22]. In brief, serum samples obtained from 10 adults and 10 children (age range, 5-19 years) who were carriers of anti-H. pylori IgG were incubated for 30 min at 37ЊC with the sonicated cell extracts of the bacterial strains, and the level of unabsorbed anti-H. pylori IgG was measured.…”

Human serum antibody response toHelicobacter pyloriwhole cell antigen in an institutionalized Bangladeshi population

“…Patients infected with these organisms have been shown to produce serum antibodies to H. pylori antigens and several studies have implied that the immune response correlates with the histological findings in biopsy specimens (Drumm et al . 1990; Aguirre et al . 1992; Schembri et al .…”

“…Strains carrying the genes encoding the cytotoxin-associated protein (cagA) are associated with duodenal ulcers and gastric cancer (Aucher et al 1998). Patients infected with these organisms have been shown to produce serum antibodies to H. pylori antigens and several studies have implied that the immune response correlates with the histological ®ndings in biopsy specimens (Drumm et al 1990;Aguirre et al 1992;Schembri et al 1993). The detection of antibodies speci®c for strains of H. pylori has demonstrated the value of serology for providing evidence of infection.…”

Évaluation d’un nouveau test sérologique (Pylorix®) dans une zone de haute prévalence de l’infection à Helicobacter pylori

“…Avant d'utiliser un test évalué ailleurs (surtout en occident), il faudrait une validation interne. En effet, certains auteurs ont montré que les seuils recommandés par les fabricants ne correspondent pas toujours au seuil idéal dans une population donnée et que l'éta-blissement d'une courbe ROC permettait de déterminer ce seuil [33][34][35].…”