The treatment of duodenal ulcers has changed from reducing acid production to treating the underlying Helicobacter pylori infection. Various methods are used to detect the presence of H. pylori infection and determine the effectiveness of the treatment modalities. Rollán and associates compared the diagnostic accuracy of various invasive and noninvasive tests used to determine the presence of H. pylori infection after antibiotic therapy.

A total of 59 patients with active duodenal ulcer (defined as a circumscribed break in the duodenal mucosa that measured at least 5 mm in diameter) were enrolled in the study and were consecutively assigned to two treatment groups. One group received 40 mg of famotidine once a day for six weeks. During the first two weeks, 750 mg of amoxicillin and 500 mg of metronidazole three times daily were also added. The other group received 20 mg of omeprazole two times a day for four weeks. After the first two weeks, 750 mg of amoxicillin and 500 mg of tinidazole two times a day were added for the last 14 days.

Patients were assessed four to six weeks after completion of therapy. Modalities included carbon-14 urea breath test (UBT), determination of serum IgG antibody levels and multiple antral biopsies for rapid urea testing, histology, Warthin-Starry stain and polymerase chain reaction to detect H. pylori DNA. Infection status was determined by the concordance of test results.

H. pylori was eradicated in 80 percent of the patients studied. The UBT and the rapid urease test had the best sensitivity and specificity. Serology and histology had little diagnostic value because of the high rate of false-positive results.

The authors conclude that the carbon 14 urea breath test is as accurate in determining H. pylori status after antibiotic treatment as rapid urease testing and Warthin-Starry stain. They consider the urea breath test to be the gold standard for confirmation of eradication of H. pylori infection.