RT Journal Article SR Electronic T1 Simultaneous free and bound radioactive vitamin B12 urinary excretion test JF Journal of Clinical Pathology JO J Clin Pathol FD BMJ Publishing Group Ltd and Association of Clinical Pathologists SP 611 OP 613 DO 10.1136/jcp.18.5.611 VO 18 IS 5 A1 Bell, T. K. A1 Bridges, J. M. A1 Nelson, M. G. YR 1965 UL http://jcp.bmj.com/content/18/5/611.abstract AB The absorption of vitamin B12 following the simultaneous administration of 58Co B12 and a complex of 57Co B12 with human gastric juice was assessed by measurement of urinary excretion of radioactivity. Sixteen control subjects, 13 patients with pernicious anaemia, and four who had had total gastrectomy were studied. The method proved a reliable means of detecting those with intrinsic factor deficiency.