Gastric analysis in selected populations. Improvement of its clinical usefulness.

Little doubt exists concerning the limited usefulness of gastric analysis as a screening test in unselected populations. Reliable tests, such as those for glycemia, are also of limited value when performed blindly on the general population. When, however, gastric analysis is performed on an adequate preselected population, it has a valuable role in the diagnosis and management of several gastroduodenal diseases. Highly satisfactory results can be obtained when the proper population is selected because errors are minimized due to an increased prevalence of diseases. We have verified the reliability of two types of gastric analyses: the conventional method of gastric analysis based on measurement of acid output alone (CGA) and the so-called gastroionogram (GIG), in 100 consecutive gastric analyses using the method proposed by Kronborg. Gastroionogram increases specificity (even at the risk of decreasing sensitivity) and provides an excellent predictive value of the test. With the same conditions CGA is less useful because of the overlapping among normal and diseased groups. It is useful, however, for separating patients into three groups of normal secretors, hyposecretors and hypersecretors.