Detection of protein bound vitamin B12 malabsorption. A case report and review of the literature.
The Schilling test is used to identify the cause of vitamin B12 malabsorption in patients with low serum vitamin B12 levels. The initial step required for vitamin B12 absorption is a process of separation from the protein complexes of food. The crystalline Co-57 vitamin B12 used 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 B12 bound to protein has been developed. The authors describe a patient with protein-bound vitamin B12 malabsorption whose crystalline Co-57 vitamin B12 stage I Schilling test was normal. A subsequent stage I Schilling test using Co-57 vitamin B12 bound to chicken serum revealed significant cobalamin malabsorption. A review of the history and literature of this diagnostic test using protein bound vitamin B12 is also presented.
Department of Radiology, E.L. Saenger Radioisotope Laboratory, University of Cincinnati Medical Center, OH 45267-0577.
M H
MH
Lucas
A H
AH
Elgazzar
D000368:Aged; D000818:Animals; D002645:Chickens / Q000097:blood; D003037:Cobalt Radioisotopes; D005260:Female; D006801:Humans; D012546:Schilling Test / Q000379:methods*; D014805:Vitamin B 12; D014806:Vitamin B 12 Deficiency / Q000175:diagnosis*
D003037:Cobalt Radioisotopes; D014805:Vitamin B 12