4. Eligible potential subjects (meeting all inclusion and no exclusion criteria) are asked to participate in study with informed consent. The study will be introduced to potential subjects by the emergency physician caring for this patient. The study will be introduced only after CT for evaluation of abdominal pain and tenderness is ordered by the physicians caring for the patient, as this is a study inclusion criterion. Potential subjects who do not give informed consent to participate are recorded in electronic research log but not enrolled in study. No identifiers are recorded for these patients. Recorded information includes age (if greater than 89, will simply be recorded as "greater than 89"), gender, race/ethnicity, date, and reason for exclusion. No identifiers are recorded for these patients.