Accuracy of two plasma antibody tests and faecal antigen test for non-invasive detection of H. pylori in middle-aged Caucasian general population sample

Abstract

Objective: The aim of the study was to assess the accuracy of two plasma Helicobacter pylori (H. pylori) antibody test-systems and a stool antigen test (SAT) system in a general population sample in Latvia.

Materials and methods: Blood and faecal samples were analysed in healthy individuals (40–64 years), referred for upper gastrointestinal endoscopy according to pilot study protocol within a population-based study investigating gastric cancer prevention strategies (GISTAR pilot study). Antibodies to H. pylori were assessed in plasma by latex-agglutination test and enzyme-linked immunosorbent assay (ELISA). H. pylori antigen in faecal samples was detected by a monoclonal enzyme immunoassay-based SAT. Histological assessment of H. pylori based on a modified Giemsa staining method was used as the gold standard. Individuals having received H. pylori eradication within one year prior to enrolment were excluded. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and overall accuracy were calculated. Receiver-operating characteristic curves were designed to estimate the optimal diagnostic cut-off value of tests.

Results: The analysis included 779 participants for latex-agglutination test, 1002 for ELISA and 672 individual samples for SAT. The sensitivity, specificity, PPV, NPV and overall accuracy were as follows: latex-agglutination test (86;81;87;80;84%), ELISA (97;72;83;94;86%) and SAT (87;81;87;81;85%), respectively. The optimal diagnostic cut-off value for ELISA test was ≥50.26 g/L.

Conclusions: Although the performance of the three tests was comparable to each other, the three test systems showed suboptimal accuracy, with important implications for public health programs based on ‘test-and-treat’ strategy.

Keywords:

• H. pylori
• plasma antibody tests
• latex-agglutination
• ELISA
• stool antigen test

Acknowledgements

We acknowledge the contribution of the Data Safety and Monitoring Board members and administrative-managing staff of the study – Aiga Rudule, Inga Upmace, and Janis Kotlers. The study would not have been possible without the involvement of medical professional organizations, in particular Digestive Diseases Centre GASTRO, Academic Histology laboratory, Insights-A as well as municipalities and their healthcare institutions in Cesis, Aluksne, Ludza, Saldus and Tukums regions of Latvia. We appreciate the support from industry for the special conditions in supplying with reagents, equipment, medication and/or professional advice – BIOHIT, Oyj., Eiken Chemical Co., Meridian Bioscience, Inc. The study has been endorsed by European Helicobacter and Microbiota Study Group (EHMSG), Healthy Stomach Initiative (HIS) and International Digestive Cancer alliance (IDCA). Support has been provided by the Riga East University Hospital Support Foundation. We acknowledge also the support from the Ministry of Health of Latvia.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The study has been supported in part by various funding sources in the University of Latvia; this includes the funding schemes from the European Regional Development Fund (ERDF) and the National Program for Research in Latvia: Biomedicine 2014–2017. The protocol development was supported in part by the project of the European Social Fund No. 009/0220/1DP/1.1.1.2.0/09/APIA/VIAA/016 ‘Multidisciplinary Research Group for Early Cancer Detection and Cancer Prevention’.