Advantages of the plasma uptake method for measuring vitamin B12 absorption

The plasma uptake method for determining vitamin B12 absorption is reassessed. The results of this study demonstrate the ease with which normal controls can be separated from patients with intestinal malabsorption of vitamin B12 and from those with pernicious anaemia. This method is also shown to be a sensitive index of improved vitamin B12 absorption after treatment of small-intestinal disease and with the addition of intrinsic factor in pernicious anaemia. The advantages, particularly for developing countries, over the more commonly used Schilling test are discussed. It is emphasized that, because of the lack of a universally accepted normal value, healthy controls should be studied to define the normal range for the community under investigation.