trademark for a diagnostic agent for achlorhydria; it is a means of gastric analysis based on the fact that free hydrochloric acid releases a dye (Azure A) from a resin base. Once the dye is released it is absorbed from the intestinal tract and excreted in the urine. If no hydrochloric acid is present in the stomach the dye will not appear in the urine. The test is valuable as a screening device to rule out achlorhydria and is much less disturbing than other methods of gastric analysis, which require the passage of a stomach tube. It does not, however, give conclusive evidence sufficient for diagnosis of cases in which there is no secretion of hydrochloric acid.