Anemia, PerniciousGastritisAnemiaIntrinsic FactorAchlorhydriaGastritis, AtrophicAnemia, MacrocyticSchilling TestVitamin B 12Vitamin B 12 DeficiencyGastric MucosaAnemia, MegaloblasticCobalt IsotopesGastrinsParietal Cells, GastricPostgastrectomy SyndromesAnemia, HypochromicAnemia, AplasticHydroxocobalaminAnemia, HemolyticGastric JuiceFanconi AnemiaHelicobacter pyloriStomachGastroscopyHelicobacter InfectionsAnemia, Hemolytic, AutoimmuneStomach NeoplasmsAutoimmune DiseasesCarcinoid TumorEnterochromaffin CellsAutoantibodiesZollinger-Ellison SyndromeFolic Acid DeficiencyAnemia, Sickle CellMalabsorption SyndromesCobalt RadioisotopesGastric FundusAnemia, SideroblasticPolypsDuodenal UlcerEndocrine System DiseasesH(+)-K(+)-Exchanging ATPaseEthylaminesVitiligoPyloric AntrumInfectious Anemia Virus, EquineHemoglobinsAgammaglobulinemiaGastric AcidGastritis, HypertrophicAnemia, RefractoryFolic AcidEdrophonium