Modern approaches to the investigation of vitamin B12 deficiency.
The classic workup of a patient for possible PA is revisited in light of the vanishing Schilling test. The vagaries of testing for B12 and blocking antibodies are reexamined. The advantages and disadvantages of newer tests such as MMA and serum gastrin levels are catalogued. At this juncture in the evolution of new test strategies, there is a considerable controversy regarding the significance of high MMA levels in the face of normal B12 levels, particularly in the elderly. Hopefully, this controversy will soon be resolved and the newer crop of tests will be proven and accepted in the workplace. Still, the words of Alexander Pope spring to mind: "Be not the first by whom the new are tried, Nor yet the last to lay the old aside."
Ward
Patrick C J
PC
Department of Pathology and Laboratory Medicine, University of Minnesota, Duluth School of Medicine, 10 University Drive, Duluth, MN 55812, USA. path@d.umn.edu
D000752:Anemia, Pernicious / Q000175:diagnosis* / Q000209:etiology; D019138:Antibodies, Blocking / Q000097:blood; D005755:Gastrins / Q000097:blood; D006801:Humans; D007437:Intrinsic Factor / Q000276:immunology; D008764:Methylmalonic Acid / Q000097:blood / Q000652:urine; D010338:Pathology, Clinical / Q000379:methods*; D012546:Schilling Test; D014805:Vitamin B 12 / Q000097:blood / Q000276:immunology / Q000652:urine; D014806:Vitamin B 12 Deficiency / Q000097:blood / Q000175:diagnosis / Q000652:urine
D019138:Antibodies, Blocking; D005755:Gastrins; D008764:Methylmalonic Acid; D007437:Intrinsic Factor; D014805:Vitamin B 12