Abstract
Impaired absorption of vitamin B(12) has been shown by a whole body counter technique in 7 of 10 infants and children who had resection of over 45 cm of ileum. Absorption was normal in 2 patients who had 15 cm or more terminal ileum remaining. If absorption was abnormal the serum level of vitamin B(12) did not fall below the lower limit of the normal range for several years, puberty being a particularly vulnerable time. Though the site and length of the resection often suggested whether vitamin B(12) deficiency was likely to occur, an absorption test was necessary for accurate prediction and to allow treatment to be given rationally before complications occurred. The whole body counter technique was particularly suitable for children as it did not involve collection of urine or faeces, injections, or admission to hospital.