This purpose of this study was to analyze the use of abdominal computed tomography (CT) imaging in patients with possible blunt abdominal trauma. A retrospective analysis of all trauma patients over a 1-year period (1993-1994) was conducted, with prospective study protocol in 52 patients using serial abdominal exam and hematocrits (Hcts) instead of abdominal CT for evaluation of blunt abdominal trauma. Urgent abdominal CT was used as the initial diagnostic test for evaluation of blunt abdominal trauma in 813 patients over this 1-year period. CT was obtained in 379 (46.6%) of these patients who arrived hemodynamically stable (admission systolic blood pressure > or = 90), had a Glasgow Coma Scale > 13, and had admission Hct > or = 35 because of distracting injuries, possible traumatic brain injury, or alcohol/drug use, which might render the abdominal physical exam unreliable. Only 47 CT scans (12.4%) were positive, and three patients (0.8%) required laparotomy. In an effort to more efficiently use abdominal CT, we performed a prospective study in 52 patients with possible blunt abdominal trauma, admission systolic blood pressure > or = 90, Hct > or = 35, Glasgow Coma Scale > 13, and a normal abdominal exam on admission. These patients were followed with serial abdominal examinations and Hcts every 6 hours for 24 hours, and delayed CT, when applicable. CT was obtained in seven patients (13.5%) for evaluation of fall in Hct or abnormal abdominal examination; all were negative for abdominal injury. A protocol using serial abdominal exams, Hcts, and delayed abdominal CT imaging may be useful in select patients to decrease the high number of negative routine abdominal CTs that are obtained in the evaluation of blunt abdominal trauma.