• Classic pernicious anemia with abnormal Schilling test results developed in a previously described vegan patient who had coexisting subtle cobalamin malabsorption (demonstrable by abnormal ovalbumin-cobalamin absorption test results but normal Schilling test results). This suggests that the ovalbumin-cobalamin absorption test or a modified version may serve as a prodromal phenomenon to identify patients at risk for developing pernicious anemia. The patient's transformation was also accompanied by the appearance of serum anti-intrinsic factor antibody. A modified assay retrospectively detected this antibody a year earlier than did the standard assay, indicating that such modification enhances the sensitivity of this useful test.
(Arch Intern Med 1982;142:2206-2207)
Carmel R. Subtle Cobalamin Malabsorption in a Vegan PatientEvolution Into Classic Pernicious Anemia With Anti-intrinsic Factor Antibody. Arch Intern Med. 1982;142(12):2206–2207. doi:10.1001/archinte.1982.00340250172029