Tubeless gastric analysis with azuresin (Diagnex Blue), developed by Segal et al,1 when properly applied, has proved to be a reliable semiquantitative method to determine the capability of the gastric mucosa to secrete acid. Investigations by the authors have shown that this technique combined with the measurement of uropepsin activity provides the means, not only to detect chronic gastritis, but also to differentiate the three possibly sequential stages of chronic gastritis, namely, superficial gastritis, atrophic gastritis and complete atrophy. The authors correlated the histological appearance of peroral gastric mucosal biopsy specimens with the gastric acid and pepsinogen secretion determined by tubeless gastric acid analysis and the measurement of uropepsin activity, respectively. The Figure reveals the results of this comparison. All the subjects with normal gastric mucosa secreted acid; the uropepsin activity in these persons ranged between 25 and 162 units/hr, with a mean of 79 units/hr (normal range, 30