Assessment of gastric acid output by H2 breath test.

BACKGROUND

The standard method to measure gastric acid secretion is the aspiration of gastric juice. A noninvasive breath test after application of magnesium has been proposed. The aim of this study was to modify the method, to possibly improve the discriminatory value of the test in comparison with intubation tests.

METHODS

We measured the time course of the reaction of magnesium and gastric acid in vitro and determined the gastric hydrogen kinetics in humans by insufflation of hydrogen into the stomach and measuring its reappearance in the exhaled air. Thereafter, a comparison of the breath test and the intubation test was done in 10 healthy volunteers in different secretory states.

RESULTS

After hydrogen insufflation 31.4% reappeared in 90 min (16.3% exhaled, rest belched). Discriminant analysis showed that the intubation test had a good discriminatory power. On the other hand, the breath test failed to distinguish between different secretory states (stimulation, inhibition, and intermediate).

CONCLUSION

Whereas the intubation test discriminated between high and low acid secretion, the breath test did not. This test therefore seems, at least as performed here, unsuitable as a diagnostic test of gastric acid secretion.