Clinical evaluation of simultaneously administered 58Co labelled vitamin B12 and 57Co labelled vitamin B12 bound to intrinsic factor in patients with pernicious anaemia.

The clinical and laboratory data from 75 patients with altered vitamin B 12 absorption were reviewed. In 36 cases the diagnosis of pernicious anaemia had been established. Of these, 14 patients showed malabsorption of radiolabelled vitamin B 12, but the absorption of vitamin B 12 bound to the intrinsic factor (IF) was normal (Group A). The other 22 patients with pernicious anaemia showed altered free and IF-bound vitamin B 12 absorption (Group B). Laboratory and clinical data and the absorption tests (xylose and fat excretion) were more abnormal in group B than in group A. Finally, 39 patients (Group C) with general malabsorption showed alternation of the absorption of free and IF-bound vitamin B 12 (Group C). The clinical nd biological data were different in these patients from that found in groups A and B. It is possible that in patients with pernicious anaemia who are untreated an alteration of the intestinal mucosa may produce a malabsorption of vitamin B 12 even in the presence of intrinsic factor.