In a technetium-labeled red blood cell bleeding scan, blood is taken from you, and a small amount of radioactive material called technetium is added to the blood. The blood with the technetium is then injected back into your bloodstream.
Red blood cells with the technetium attached to them accumulate at the location of active bleeding. A machine scans the body to find where the technetium accumulates. This method of finding bleeding is sometimes more effective than angiography. The technetium-labeled red blood cell bleeding scan may find slow bleeding that can't be seen using angiography.
The technetium-labeled red blood cell bleeding scan is used:
If the source of the bleeding in the large intestine cannot be found using colonoscopy or other methods.
If the bleeding is too slow or intermittent to be detected by angiography.
If colonoscopy finds that the bleeding is coming from a spot in the small intestine and the bleeding does not stop. (The bleeding stops on its own in most people.)
When surgery is needed to stop the bleeding. It is important to locate exactly the source of the bleeding before surgery.