Comparison of noninvasive breath hydrogen test for gastric acid secretion to standard intubation test in infants and young children.

We have developed a noninvasive test of gastric acid secretion for use in infants and young children. It is based on the reaction of ingested magnesium metal with gastric acid to produce hydrogen gas, which is excreted in exhaled air and belches. This test was compared to the standard intubation test by performing both, on different days, in 20 children (5-37 months of age) without known gastric disease. The results of the two tests compared well: correlation coefficients were 0.78, 0.75, or 0.72 when exhaled air was collected for a total of 56, 81, or 31 min, respectively. Because the test is noninvasive, it should be more acceptable to children and their parents than the intubation test and thus could be used to conduct studies which are currently impractical.