Absorption of protein-bound vitamin

Atrophic gastritis will cause decreased secretion of gastric acid before there is any impairment of intrinsic factor secretion. This means that the absorption of crystalline vitamin B12, as used in the Schilling test, is normal but the absorption of protein-bound vitamin B12 from foods will be impaired (Section 10.7.1), and the Schilling test will give a false-negative result. 

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