The current gold standard test for diagnosis of Helicobacter pylori involves histological staining and/or urease testing of antral biopsy specimens. However, these methods are invasive, and alternative non-invasive methods, i.e. the urease breath test and serological tests, are available. The test for H. pylori-specific serum immunoglobulin G (IgG) is now available commercially. The aim of this study was to compare the gold standard tests for diagnosis of H. pylori to the non-invasive method of detecting IgG antibody in the serum. Two hundred and twenty-five (225) subjects were tested for H. pylori by histological staining, urease testing, direct microscopy of antral biopsy specimens and quantification of serum IgG antibody. The population examined was divided into 2 groups--a group of 52 patients with no gastrointestinal symptoms and a group of 173 patients with dyspepsia. Out of 173 dyspeptic patients, 22 (12.7%) were false-positive to H. pylori. Out of 52 non-dyspeptic subjects, 30 (57.7%) were false-positive (p < 0.0001). The sensitivity and specificity were 91.6% and 51.7%, respectively. The specificity and positive predictive value increased by approximately 30% when the subjects examined were in the younger age group (< 30 years), while the sensitivity and the negative predictive value did not change significantly. This study indicates that serological testing is not recommended for diagnosis nor is it recommended for follow-up treatment, especially among the older age group (> 30 years).