Detection of Protein Bound Vitamin B12MalabsorptionA Case Report and Review of the Literature

摘要

The Schilling test is used to identify the cause of vitamin B12malabsorption in patients with low serum vitamin B12levels. The initial step required for vitamin B12absorption is a process of separation from the protein complexes of food. The crystalline Co-57 vitamin B12used in the Schilling test does not reproduce this physiologic process. Thus, a crystalline stage I Schilling test may be normal even in the face of cobalamin malabsorption. An adjunctive stage I Schilling test using Co-57 vitamin B12bound to protein has been developed.The authors describe a patient with protein-bound vitamin B12malabsorption whose crystalline Co-57 vitamin B12stage I Schilling test was normal. A subsequent stage I Schilling test using Co-57 vitamin B12bound to chicken serum revealed significant cobalamin malabsorption. A review of the history and literature of this diagnostic test using protein bound vitamin B12is also presented.