The stool antigen test for detection of Helicobacter pylori after eradication therapy

Current noninvasive tests to confirm the eradication of Helicobacter pylori must be performed 4 weeks or more after eradication therapy is completed.

To determine whether the stool antigen test, a relatively new noninvasive test for H. pylori, administered at various times after eradication therapy correctly identifies persons with persistent H. pylori infection.

Prospective blinded study.

Six clinical centers in the United States and Europe.

84 H. pylori --infected patients undergoing endoscopy for upper abdominal symptoms.

At baseline and on day 35 after the completion of triple eradication therapy, all patients underwent endoscopy with histologic examination, rapid urease test and culture, urea breath test, and a stool antigen test. The stool antigen test was also performed on days 3, 7, 15, 21, 28, and 35 after completion of therapy.

Compared with the gold-standard endoscopic tests on day 35 after antimicrobial therapy, the urea breath test had a sensitivity of 94% (95% CI, 71% to 100%) and a specificity of 100% (CI, 94% to 100%). The stool antigen test had a sensitivity of 94% (CI, 71% to 100%) and a specificity of 97% (CI, 89% to 100%). On day 7 after treatment, the stool antigen test was predictive of eradication (positive predictive value, 100% [CI, 69% to 100%]; negative predictive value, 91% [CI, 82% to 97%]).

A positive result on the stool antigen test 7 days after completion of therapy identifies patients in whom eradication of H. pylori was unsuccessful.