Comparative study of the value of the calcium, secretin, and meal stimulated increase in serum gastrin to the diagnosis of the Zollinger-Ellison syndrome.

To evaluate the usefulness of provocation tests in the diagnosis of the Zollinger-Ellison (ZE) syndrome stimulation tests with calcium, 15 mg/kg. 3 h, and secretin GIH, 1 U/kg.30 s, were performed in 15 patients with histologically proven or suspected ZE syndrome. Nine of these 15 patients were without previous gastric surgery and in them meal stimulated serum gastrin levels were measured as well. These tests were also performed in normal subjects and in patients with duodenal ulcer, antrectomy, total gastrectomy, and achlorhydria. All tests were considered to be positive if a more than 50% increase in serum gastrin was found. The results indicate that secretin stimulation is the provocation test of first choice in the diagnosis of this syndrome. This test is most valuable for the following reasons: (1) there were few (two out of 15) false-negative test results in ZE patients; (2) there were no false-positive tests in 69 patients without gastrinoma; (3) it was easy and quick to perform; and (4) there were no adverse reactions. The two ZE patients with negative secretin stimulation tests had negative calcium provocation tests as well, in spite of histologically proven gastrinoma. In 11 patients with suspected or proven ZE syndrome and basal serum gastrin levels of less than 1000 pg/ml a rather good correlation (r = 0-841; P less than 0-01) was found between the percental increase in serum gastrin after stimulation by calcium and secretin. Meal stimulated serum gastrin levels are helpful only in patients without previous gastric surgery.