Objective: The aim of this study was to compare the performance characteristics of one serum and four whole blood rapid antibody tests for Helicobacter pylori infection.
Methods: A total of 97 outpatients referred for endoscopic evaluation of dyspepsia were included. Antral biopsies were obtained for histology and rapid urease test. Serum was tested with an enzyme-linked immunoassay (HM-CAP) and a rapid serology test (FlexSure HP). A commercially available 13C-urea breath test was performed. Capillary blood obtained by fingerstick was tested with FlexSure HP, QuickVue, Accustat, and StatSimple pylori tests. Sensitivity, specificity, and accuracy of each rapid test was calculated relative to a criterion standard of histological gastritis and at least two of the four following tests positive: identifiable organisms on specially stained slides, rapid urease test, urea breath test, or serum immunoassay.
Results: A total of 30 patients (31%) were infected. The FlexSure HP Serum, and FlexSure HP, QuickVue, Accustat, and StatSimple pylori whole blood tests had sensitivities of 90%, 87%, 83%, 76%, and 90%; specificities of 94%, 90%, 96%, 96%, and 98%, and accuracies of 93%, 88%, 92%, 87%, and 96%, respectively. Sensitivities were not statistically different. StatSimple pylori was more specific than FlexSure HP whole blood (p<0.03), and more accurate than FlexSure whole blood (p<0.024) and Accustat (p< 0.01). Serum immunoassay was significantly more sensitive (97%) than FlexSure whole blood, QuickVue, and Accustat (p<0.01), but its specificity (95%) was not statistically different from the rapid tests.
Conclusion: Rapid antibody testing provides an accurate diagnosis of H. pylori infection. In general, these tests are less sensitive than, but as specific as, standard serology.