Comparison of Non-Invasive Tests for H. pylori Infection in Children
Abstract & Commentary
Hal B. Jenson, MD, FAAP Chair, Department of Pediatrics, Director, Center for Pediatric Research, Eastern Virginia Medical School and Children’s Hospital of the King’s Daughters, Norfolk, VA, is Associate Editor for Infectious Disease Alert
Synopsis: A multicenter study of 4 non-invasive tests for Helicobacter pylori infection in children and adolescents showed the urea breath test to be the preferred diagnostic test, with the greatest sensitivity among all age groups.
Source: Mégraud F, et al. Comparison of Non-Invasive Tests to Detect Helicobacter pylori Infection in Children and Adolescents: Results of a Multicenter European Study. J Pediatr. 2005;146:198-203.
An open, prospective, multicenter, multinational European study compared biopsy-based H. pylori tests with 4 non-invasive tests for H. pylori infection: urea breath test, stool antigen test, and antibody detection in serum and urine. The H. pylori status was defined after endoscopy of 473 children and adolescents 2-17 years of age. Of these, 316 completed all 4 non-invasive tests, including 133 who were positive for H. pylori by either culture from endoscopy or positive histology and rapid urease test. All tests were performed within a 1-week interval.
The 13C-urea breath test was performed on fasting children (> 4 hours after the last meal). A typical test meal consisted of 150 mL of orange or apple juice, followed by 13C-labeled urea dissolved in 20 mL of juice, with another 30 mL used to rinse the mouth of tracer. Blinded analysis was performed by mass spectrometry on expired air samples collected before, and 30 minutes after, urea ingestion. A baseline value of > 4 per mL was considered to be the threshold for positivity.
The sensitivity and specificity of the tests were: urea breath test, 96% and 97%; stool antigen, 73% and 97%; serum antibody, 89% and 93%; and urine antibody, 63% and 97%. Except for the stool antigen test, there was a trend toward greater sensitivity of the tests with increased age. The positive and negative predictive values were: urea breath test, 96% and 97%; stool antigen, 95% and 83%; serum antibody, 91% and 92%; and urine antibody, 94% and 78%.
Comment by Hal B. Jenson, MD, FAAP
The most reliable method for diagnosis of H. pyloriinfection is by culture or histology of biopsy samples obtained by endoscopy. In the United States, culture is not often readily available. Under these circumstances, histology combined with a rapid urease test is the practical gold standard.
A sensitive and accurate non-invasive test remains elusive. The urea breath test appears to be the non-invasive test of choice for diagnosis of H. pylori infection. It showed excellent sensitivity across all ages. Several studies from Europe and Canada confirm its usefulness, although it is cumbersome, time-consuming, of limited reliability among children < 2 years of age and, most importantly, does not currently have FDA approval, and physicians are not reimbursed for its use.
Detection of antibody in serum appears to give adequate results, and was the second most sensitive test. However, serologic diagnosis is hampered by 2 factors. First, the serum IgG level in untreated patients may remain at high, stable titers for prolonged periods and, therefore, a positive result may reflect remote infection. Second, children appear to have lower serologic response, which results in greatly decreased diagnostic sensitivity for children < 7-9 years of age.
The stool antigen test, using a polyclonal antibody, showed low sensitivity. Newer stool antigen tests using monoclonal antibodies hold greater promise, and may overcome the problems of variation according to age and inter-test variation. A urine antigen test is available in Japan, but these tests have not proved reliable and accurate for diagnosis.
A multicenter study of 4 non-invasive tests for Helicobacter pylori infection in children and adolescents showed the urea breath test to be the preferred diagnostic test, with the greatest sensitivity among all age groups.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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