Diagnosis of achlorhydria by plasma secretin determination--a tubeless approach.

To investigate the value of plasma secretin determination in the diagnosis of impaired gastric secretion, blood samples were drawn for secretin assay (radioimmunoassay) at specified intervals before and after pentagastrin stimulation in 10 healthy volunteers and 11 subjects with suspected hypo- or achlorhydria (less than 10 mEq HCl/2 h). The tests were performed twice, once with and once without aspiration of gastric juice for estimation of acid output. In six other patients with proven achlorhydria, the test was performed once without gastric aspiration. The best discrimination of a single plasma secretion level between controls and patients with hypo- and achlorhydria was obtained 60 min after pentagastrin stimulation. All controls and four subjects with an acid output more than 10 mEq/2 h had secretin levels within normal limits. In contrast, 12 of the 13 subjects with hypochlorhydria had abnormally low basal corrected secretin levels at 60 min, including nine achlorhydria patients. It is concluded that secretin determinations after pentagastrin stimulation may be a valuable diagnostic and epidemiological tool to identify patients with impaired gastric secretion.