1. False-Positive Secretin Stimulation Test for Gastrinoma Associated With the Use of Proton Pump Inhibitor Therapy 
Joshua A. Goldman, Wanda P. Blanton, David W. Hay, M. Michael Wolfe 
Clinical Gastroenterology and Hepatology 
Volume 7, Issue 5, Pages (May 2009)
DOI: /j.cgh
Copyright © 2009 AGA Institute Terms and Conditions

2. Figure 1
False-positive secretin test associated with PPI therapy and subsequent normalization of the test after cessation of PPI. While the patient was on PPI therapy (dashed lines), the serum gastrin levels increased by more than 200 pg/mL in response to secretin injection. After cessation of PPI therapy for 2 weeks (solid lines), the response to the secretin test was normal.
Clinical Gastroenterology and Hepatology 2009 7, DOI: ( /j.cgh )
Copyright © 2009 AGA Institute Terms and Conditions

3. Figure 2
Proposed mechanism of positive secretin stimulation testing in hypochlorhydria/achlorhydria. Under normal physiologic conditions (left), secretin stimulates D-cell expression of somatostatin, resulting in a net decrease in G-cell gastrin secretion. In contrast, in a gastrin-producing tumor (center), no somatostatin-producing D cells are present (denoted by X), and, as a result, secretin stimulates gastrin release without any opposing effects from somatostatin. Similarly, in situations characterized by hypochlorhydria (right), such as chronic atrophic gastritis or the use of potent antisecretory agents (eg, PPIs), the increased intragastric pH decreases somatostatin expression in D cells (denoted by X), disrupting the negative feedback loop governing gastrin release, thereby allowing unopposed secretin-stimulated gastrin release from G cells to yield a false-positive test result.
Clinical Gastroenterology and Hepatology 2009 7, DOI: ( /j.cgh )
Copyright © 2009 AGA Institute Terms and Conditions