Orgler et al. recommend that patients with nonspecific GI symptoms and/or iron deficiency—with or without anemia—should be evaluated for AIG through laboratory testing that includes PCA, IFA, and serum gastrin, in addition to a complete blood count, measures of iron status (transferrin saturation, transferrin, ferritin), and measures of B12 status [10]. Here, GAST is linked to anemia (phenotype).