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Helicobacter pylori infection is linked to approximately 80% and 90% of gastric and duodenal ulcers, respectively. The H pylori stool antigen (HpSA) test is a new tool for evaluating infection. In a recent study, reported in the Journal of Gastroenterology and Hepatology (August 2005), Masanori Ito, MD, and colleagues investigated the clinical usefulness of the HpSA test, compared with the 13C-urea breath test (UBT), in evaluating bacterial eradication therapy. Patients (n = 105) with H pylori infection received appropriate antibiotic eradication therapy (eg, amoxicillin, tetracycline), and the results were evaluated after 8 weeks.
Of these patients, 24% and 19% tested positive with the UBT and the HpSA test, respectively. Discordant results were seen in 8.6% of the patients (7 with UBT+ and HpSA-and 2 with UBT-and HpSA+). Five of the patients were determined to have false-positive results with the UBT. Final diagnostic accuracies of the UBT and the HpSAtests were 94.3% and 97.1%, respectively. In cases of weakly positive UBT values, the HpSA test was used to diagnose the correct status of infection after eradication in 99% of all patients. For the clinical evaluation of eradication therapy, a combination of both tests is recommended.