Total Body Counting in the Assessment of Vitamin B₁₂ Absorption in Patients with Pernicious Anemia, Achlorhydria Without Pernicious Anemia and in Acid Secretors

The absorption of ⁵⁸Co-vitamin B₁₂ was assessed by the method of total body counting in 25 patients with frank P.A., five with latent P.A., 47 with achlorhydria but without malabsorption of vitamin B₁₂ and 47 acid-secreting patients. A total of 192 tests was done. With or without prior stimulation of intrinsic factor secretion by pentagastrin the upper level of absorption of vitamin B₁₂ in patients with frank or latent P.A. was 25 per cent. Taking an equivocal result to be 21-25 per cent inclusive, the total body counting method was able to distinguish P.A. patients from those with achlorhydria without P.A. with 87 per cent accuracy and one per cent error and from non-P.A. achlorhydric patients and acid secretors combined with 91 per cent accuracy and 0.5 per cent error.

Pentagastrin stimulation did not improve the separation between achlorhydric patients with and without P.A. but raised the lower limit of retention of vitamin B₁₂ from 24 to 44 per cent in the acid secreting patients.

The method of total body counting is recommended as a method of assessing vitamin B₁₂ absorption.