Indium 111 Autologous Tagged Leukocytes in the Diagnosis of Intraperitoneal Sepsis

We report the results of a new test, indium oxine In 111 scanning, in the diagnosis of postoperative infection. Indium 111 was used to label autologous polymorphonuclear leukocytes, which when reinjected migrate to sites of infection, inflammation, or both. Standard scintigraphy localizes the labeled inflammatory cells at these sites. Sixty-six scans were performed in 43 surgical patients. Thirty-seven scans were categorized as true-positive; 19 scans were categorized as true-negative. Therefore, the accuracy rate was 85%. Two scans (3%) in one patient represented false-positive results. Two scans (3%) were positive for inflammation but there was no infection present; this group was denoted as equivocal. Six scans (9%) were false-negative; false-negative scans are more likely in old lesions with poor blood supply and in areas that overlap regions of normal uptake. The noninvasive nature of the test, high accuracy rate, and ease of administration make it a potentially useful tool in the diagnosis of postoperative infection.