In many cases the gastroenterologist or surgeon will begin the evaluation with upper and/or lower endoscopy. If this is not diagnostic then next step is a labeled RBC NM bleeding scan. This examination can detect bleeding as little as 0.1cc/min and usually will give an approximate location of the site of bleeding e.g. right colon vs. small bowel. If the bleeding scan is unsuccessful or if catheter-based treatment is desired, an angiogram of the abdomen and pelvis will be performed. Angiography can detect active bleeding at a rate of 1-2cc/min. Treatment options, if a specific site of bleeding is identified, include vasopressin to provoke vasoconstriction. A last option is arterial or venous embolization.