ASSESSMENT OF GASTRIC-ACID OUTPUT BY H-2 BREATH TEST

Background: The standard method to measure gastric acid secretion is t he aspiration of gastric juice. A noninvasive breath test after applic ation of magnesium has been proposed. The aim of this study was to mod ify the method, to possibly improve the discriminatory value of the te st in comparison with intubation tests. Methods: We measured the time course of the reaction of magnesium and gastric acid in vitro and dete rmined the gastric hydrogen kinetics in humans by insufflation of hydr ogen into the stomach and measuring its reappearance in the exhaled ai r. Thereafter, a comparison of the breath test and the intubation test was done in IO healthy volunteers in different secretory states. Resu lts: After hydrogen insufflation 31.4% reappeared in 90 min (16.3% exh aled, rest belched). Discriminant analysis showed that the intubation test had a good discriminatory power. On the other hand, the breath te st failed to distinguish between different secretory states (stimulati on, inhibition, and intermediate). Conclusion: Whereas the intubation test discriminated between high and low acid secretion, the breath tes t did not. This test therefore seems, at least as performed here, unsu itable as a diagnostic test of gastric acid secretion.