OBJECTIVE To compare the accuracies and complication rates of diagnostic peritoneal lavage (DPL) in trauma patients with and without previous abdominal surgery. METHODS A retrospective review of DPL accuracy and complication rate was performed using all ED trauma patients who underwent DPL during 1993 as identified by the trauma registry. Care was provided at a Level-1 trauma center, a 1,100-bed, central-city teaching hospital with an annual ED census of 84,000. Records were reviewed for a history of previous surgery, DPL results, complications, mechanism of injury, and location of abdominal scars. DPL was performed using the Seldinger technique with a standard Arrow Diagnostic Peritoneal Lavage Kit using an 8-Fr catheter. Rates for patient groups with and without previous abdominal surgery were compared using Fisher's exact test. A "misclassified" DPL was defined as either a positive DPL with negative laparotomy or a negative DPL with subsequent need for laparotomy. "Complications" were defined as iatrogenic injury during the procedure or inability to obtain return of fluid during the lavage. RESULTS A total of 372 DPLs were performed; 42 in patients with previous surgery and 330 in patients without prior surgery. The groups were similar with respect to proportion with blunt trauma (95% vs 97%), positive DPL (19% vs 19%), misclassified rate (2.4% vs 1.8%), and complication rate (2.4% vs 0.9%); no significant difference was found between groups. The previous abdominal surgeries were appendectomy (n = 20), tubal ligation (n = 5), abdominal hysterectomy (n = 4), cholecystectomy (nonlaparoscopic) (n = 4), pyloric stenosis (n = 1), uterine prolapse (n = 1), undescended testis (n = 1), partial gastrectomy (n = 1), and unknown (n = 5). The analysis had a 90% power of detecting a 10% difference between the 2 groups. CONCLUSIONS The complication rate and accuracy of closed DPL in patients with previous abdominal surgery were similar to those for DPL performed in patients without previous abdominal surgery.