Accuracy of the stool antigen test for the diagnosis of childhood Helicobacter pylori infection: a multicenter Japanese study.

OBJECTIVE

The (13)C-urea breath test (UBT) has been accepted as a reliable noninvasive test for detecting Helicobacter pylori infection. Recently, another noninvasive test, a new enzyme immunoassay for H. pylori antigens in stool, has been widely investigated for its clinical usefulness. The purpose of this multicenter study was to evaluate the diagnostic accuracy of the stool antigen test in Japanese children.

METHODS

A total of 264 children (148 male and 116 female; mean age 9.2 yr, range 2-17 yr) who underwent (13)C-UBT and the stool antigen test were studied. The diagnosis in these patients was gastritis (n = 49), gastric ulcer (n = 4), duodenal ulcer (n = 24), recurrent abdominal pain (n = 43), and other conditions (n = 144). The stool antigen test was performed using the HpSA ELISA (Premier Platinum HpSA, Meridian Diagnostics). According to manufacturer's instructions, an absorbance at 450/630 nm of <0.100, > or =0.120, and 0.100-0.119 was defined as negative, positive, and indeterminate, respectively. Based on the (13)C-UBT with a cutoff value of 3.5 per mil, the performance of HpSA was studied. In 21 patients who received eradication therapy, the HpSA was performed at baseline and at 1, 2, and 6 months after completion of therapy. Eradication of H. pylori was confirmed by (13)C-UBT at 2 or 3 months of follow-up.

RESULTS

(13)C-UBT showed that 76 children were infected with H. pylori and 188 were not infected. In these same children, HpSA results were positive in 77 children, negative in 183, and indeterminate in four. The overall sensitivity, specificity, and accuracy of the test were 96.0% (95% CI = 88.6-99.2%), 96.8% (95% CI = 94.2-99.3%), and 96.5% (95% CI = 94.3-98.8%), respectively. There were no significant differences in these results among age groups of < or =5, 6-10, and > or =11 yr. Receiver operating characteristic curve analysis demonstrated that the best cutoff value of absorbance at 450/630 nm was 0.110. When a single cutoff value of 0.110 without indeterminate results was used, the sensitivity, specificity, and accuracy were 96.1% (95% CI = 90.8-99.7%), 96.3% (95% CI = 93.6-99.0%), and 96.2% (95% CI = 93.9-98.5%), respectively. In 19 patients in whom H. pylori was successfully eradicated, HpSA results were negative at 1 month of follow-up and remained negative through 6 months.

CONCLUSIONS

The HpSA is an accurate test for the detection of H. pylori infection in all age groups of children.