ABSTRACT
In vitro gastrointestinal (GI) bleed testing such as the UltraTag kits has been successfully used for a number of years. None of the research studies identified reported any significant bone marrow and liver uptake. An 80-y-old male patient was admitted to the hospital for rectal bleeding. An initial GI bleed study using the UltraTag kit was normal. Two days later, a second GI bleed scan was performed while the patient was undergoing blood transfusion with packed red blood cells. The technologist withdrew a blood sample from the blood transfusion bag. The second GI bleed test demonstrated unusual liver and bone marrow uptake. We believe that this liver uptake might have been caused by the labeling of fragmented red blood cells or oxidation of pertechnetate in the form of technetium dioxide.