A bleeding site in the small intestine is sometimes difficult to detect by conventional x-ray diagnostic techniques. Radioactive-tagged red blood cells will appear in the blood and can be obtained from the region of the bleeding site by segmental tubal aspiration. A standardized procedure will yield useful information preoperatively, provided that active bleeding takes place during the period of aspiration. The case history of a woman, aged 60, who had suffered for 9 years with a severe anemia of undetermined origin, illustrates the principles involved.
Pillow RP, Hill LD, Ragen PA, Siemsen JS, Walker LA. Newer Methods for Localization of Obscure Small-Bowel Bleeding. JAMA. 1962;179(1):23–26. doi:10.1001/jama.1962.03050010025005