The Gastrointestinal Bleeding Study detects the extravasation of radio labeled red blood cells from the vascular space into the gastrointestinal lumen. The subsequent movement of the extravasated red blood cells within the gastrointestinal lumen secondard to peristalsis allows localization of the site of bleed along the gastrointestinal tract.


  • Localization of gastrointestinal bleeding sites.
  • Localization of non-gastrointestinal bleeding sites.

Study Description

The patient will have some blood drawn that will be used in the Red Cell tagging process. It takes about 45 minutes to tag the patient’s red cells with the radiopharmaceutical. The tagged cells will then be reinjected intravenously and serial images will be acquired for 1-2 hours.

Examination Time

  • Approximately 2 hours (Images acquired for approximately 1 to 1 ½ hours) (Variable depending on whether and when the site of bleeding is identified.)
  • The study may be terminated as soon as the bleeding site is identified and confirmed by a radiologist.
  • Imaging can be performed for up to 36 hours with a single injection of radiopharmaceutical. Usually the patient will not tolerate lying under the camera for more than three hours at a time. However, imaging may be stopped and restarted.

Patient Preparation

  • Ensure the patient is not pregnant or breastfeeding.
  • No BARIUM studies for 48 hours prior to exam (unless exam is an emergency)