Significance of repeating diagnostic peritoneal lavage.

The value of repeating diagnostic peritoneal lavage (DPL) when initial results are indeterminate or negative has not been defined. From January 1974 to June 1980, 1884 patients underwent DPL. Ninety-six had repeat DPL. Eighty-eight (4.7%) patients with indeterminate initial DPL results had repeat DPL. Results were true positive in 20, false positive in non, false negative in three, and true negative in 64 patients. If results for all 88 patients had initially been considered positive and all had undergone operation, the additional yield would have been low, three patients (3.4%); 64 patients would have undergone unnecessary laparotomy. If all 88 results had been considered negative, 20 patients (23%) with intra-abdominal injuries would have been diagnosed late or not at all. Eight patients with initial negative DPL but with persistent abdominal pain underwent repeat DPL. Results were true positive in three, false negative in one, and true negative in four. Repeat lavage has an accuracy of 95.8%, sensitivity of 85.2%, and specificity of 100%; with repeat lavage, DPL overall has high accuracy (98.4%), sensitivity (94.2%), and specificity (99.7%). Repeat lavage can be helpful in evaluating patients with initial negative lavage but with persistent abdominal pain. Repeat lavage is also indicated when initial results are indeterminate.