The diagnosis of iron deficiency in patients with Crohn's disease.

Red cell indices were determined and bone marrow was examined in a selected group of 21 patients with Crohn's disease who had a routine peripheral blood picture suggestive of iron deficiency. Only nine (43%) of these patients had no stainable iron stores in the marrow fragments and could be considered as being definitely iron deficient. All indirect measurements in the diagnosis of iron deficiency, except the total iron-binding capacity (TIBC), appeared likely to result in over-diagnosis. Iron-deficient erythropoiesis, without true deficiency, may be due to the inflammatory disease process and this study indicates that the examination of bone marrow aspirate is necessary for the certain diagnosis of iron deficiency in Crohn's disease.