The assessment of gastric acidity and appraisal of its clinical value.

Abstract

Summary: Gastric intubation is necessary for the adequate assessment of gastric acidity. There is little place for the tubeless techniques. The most useful measurements are of acid concentration and secretion in the basal or fasting state and following maximal stimulation. The augmented histamine test has largely been replaced by the use of pentagastrin which has proved equally reliable and more acceptable to the patient. Indirect stimulation with insulin-induced hypoglycaemia is useful in selected patients following vagotomy. In patients with duodenal ulceration, acid secretion tests will be of value in only a small percentage of difficult diagnostic problems. There is no indication that they will assist the selection of the type of operation. Acid studies may be of value in the post-operative patient to assess the likelihood of recurrent ulceration. They are unreliable when used to differentiate benign from malignant gastric ulcers. When used in association with serum gastrin levels and measurements of gastrointestinal protein loss, gastric acid secretion studies may be of value in the differentiation of causes of hypertrophic gastric mucosa. They are of little clinical value however in other types of chronic gastritis. Newer techniques allowing measurement of back diffusion of hydrogen ions across the gastric mucosal barrier promise a better understanding of the pathogenesis of a variety of gastric diseases.