Vitamin B12 absorption in patients with continent ileostomy.

Vitamin B12 absorption was studied in 34 patients, 10 months to 6 years after construction of a continent ileostomy. Normal Schilling test values (greater than 10 percent) were obtained in 21 of the cases after a single determination. Repeated tests showed a normal B12 absorption in 8 of the 13 patients who had revealed a Schilling test value below 10 percent at the first determination. In the remaining 5 patients, repeated Schilling tests showed borderline values (5-10 percent) in 4 cases and a low value (mean 4.5 percent) in one case. One of the patients with borderline values had previously undergone resection of 80 cm of the terminal ileum. When vitamin B12-intrinsic factor complex was instilled directly into the reservoir in 3 patients, it was found that the vitamin was absorbed by the mucous membrane of the reservoir. The construction of a continent ileostomy reservoir thus does not appear to expose the patient to an increased risk of developing vitamin B12 malabsorption.