Serodiagnosis of Helicobacter pylori infection: an evaluation of a commercially available ELISA-IgG.

Background: Our aim was to evaluate a commercially available ELISA (Pyloriset IgG, Orion diagnostica, Imphos B.V.) for detection of serum IgG antibodies to Helicobacter pylori.

Methods: Serum samples were taken from 154 Dutch patients. As a reference method several biopsy specimens were taken from different gastric areas for histological analysis, bacterial culture and direct urease testing. The sensitivity, specificity, positive and negative predictive values of the Pyloriset IgG were calculated as compared to the reference method.

Results: Of 154 patients 126 were found to be H. pylori positive (82%), 28 were H. pylori negative (18%). Using a cut-off value at a titre of 500 U/l (as advised by the manufacturer) we found a sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 81, 89, 97 and 51%, respectively. Lowering the cut-off value to 350 U/l and excluding patients aged above 70 years optimalized the performance of the Pyloriset IgG to a sensitivity, specificity, PPV and NPV of 92, 96, 99 and 72%, respectively. In the subgroup of 54 patients under the age of 45 years a sensitivity, specificity, PPV and NPV of 92, 100, 100 and 82% was found.

Conclusions: The Pyloriset IgG is a simple and accurate method for detecting H. pylori infection in dyspeptic Dutch patients. The performance of this assay is improved by lowering the cut-off value (test becomes predominantly more sensitive) and excluding older patients (test becomes predominantly more specific). Therefore serology might eventually replace endoscopy or breath tests in the detection of H. pylori infection, especially in the younger age groups.