Anyone with a Glasgow-Blatchford Bleeding Score above 0 (see discharge section below); consider the clinical Rockall risk score too
Age >60yr
Transfusion required
If Glasgow-Blatchford Bleeding Score of 0 (<1% chance of requiring intervention):.  Must meet ALL of the following:
BUN <18
hemoglobin >13 (men), hemoglobin >12 (women)
Systemic BP >110
Heart rate <100
Patient did NOT present with melena
Patient did NOT present with syncope
No hepatic disease
No cardiac failure
Undifferentiated upper gastrointestinal bleeding
Peptic ulcer disease 
Lower gastrointestinal bleeding
Gastritis/esophagitis
Acute gastric dilatation
Gastric/esophageal varices
Splenic infarction
Mallory-Weiss tear