Because the radioimmunoassays used in these 14 cases do not yield comparable results that could be used interchangeably with the chemiluminometric (Immulite®) method used in our study, the fold elevation of serum gastrin concentrations above the respective URL of the assay used in that study was evaluated and distinguished canine gastrinoma patients from both acid-suppressant-naïve and acid-suppressant-treated CE dogs with a high sensitivity and specificity. This evidence concerns the gene GAST and gastrin-producing neuroendocrine tumor.