and lower bleeding in some cases can be difficult. The severity of an upper GI bleed can be judged based on the Blatchford score or Rockall score. The Rockall score is the more accurate of the two. As of 2008 there is no scoring system useful for lower GI bleeds. Clinical Gastric aspiration and or lavage, where a tube is inserted into the stomach via the nose in an attempt to determine if there is blood in the stomach, if negative does not rule out an upper GI bleed but if positive is useful for ruling one in. Clots in the stool indicate a lower GI source while melana stools an upper one. Laboratory testing Recommended laboratory blood testing includes: cross-matching blood, hemoglobin, hematocrit, platelets, coagulation time, and electrolytes. If the ratio of blood urea nitrogen to creatinine is greater than 30 the source is more likely from the upper GI tract. Imaging A CT angiography is useful for determining the exact location of the bleeding within the gastrointestinal tract. Nuclear scintigraphy is a sensitive test for detecting occult gastrointestinal bleeding when direct imaging with upper and lower endoscopies are negative. Direct angiography allows for embolization of a bleeding source, but requires a bleeding rate faster than 1mL/minute. Prevention In those with significant varices or cirrhosis nonselective β-blockers reduce the risk of future bleeding. With a target heart rate of 55 beats per minute they reduce the absolute risk of bleeding by 10%. Endoscopic band ligation (EBL) is also effective at improving outcomes. Either B-blockers or EBL are recommended as initial preventative measures. In those who have had a previous variceal bleed both treatments are recommended. Some evidence supports the addition of isosorbide mononitrate. Testing for and treating those who are positive for H. pylori is recommended. Transjugular intrahepatic portosystemic shunting (TIPS) may be used to prevent bleeding in people who re-bleed despite other measures. Among people admitted to the ICU who are at high risk, a PPI or H2RA if appears useful. Treatment The initial focus is on resuscitation beginning with airway management and fluid resuscitation using either intravenous fluids and or blood. A number of medications may improve outcomes depending on the source of the bleeding. Peptic ulcers Based on evidence from people with other health problems crystalloid and colloids are believed to be equivalent for peptic ulcer bleeding. Proton pump inhibitor (PPI) treatment before endoscopy may decrease