Limitations of indium-111 leukocyte scanning in febrile renal transplant patients.

Indium-111-labeled leukocyte scanning was evaluated as a technique for investigating possible abscess as the cause of fever in 10 renal allograft recipients under therapy for rejection, acute tubular necrosis, or urinary infection. The usefulness of the method in this setting was found to be limited by marked nonspecificity of renal, pulmonary, and other focal leukocyte accumulation. Although wound infections were correctly identified, false-positive scans resulted in multiple nonproductive consultations and radiologic procedures (some invasive) and contributed to the decision to perform one negative exploratory laparotomy. Such generalized nonspecificity in this patient population is in distinct contrast to the experience with this diagnostic test in nontransplant patients, and has not previously been reported. Possible explanations and implications of these findings are discussed. Consequently, great caution is recommended in the use of indium-111 leukocyte scans to diagnose infection in febrile renal transplant patients who present in a similar clinical setting.