Immunoscintigraphy using 555-740 MBq 99Tcm-labelled monoclonal antigranulocyte antibodies (IgG1 against NCA-95) (BW250/183) was performed in 56 patients. In 32 of them inflammatory or infectious lesions were proven or excluded histologically. Gamma camera scans were performed 4 to 6 and 20 h postinjection (p.i.). Eight of 14 infectious or inflammatory lesions could be detected in the early scan (4-6 h p.i.). Sensitivity, specificity and diagnostic accuracy of the early scan were 57, 89 and 75%. Sensitivity, specificity and diagnostic accuracy in 19 patients with bone or prosthetic bone infections (87, 81 and 84%, respectively) were lower than in patients with abdominal or soft tissue infections (100%). The overall sensitivity, specificity and diagnostic accuracy of the 20 h scan was 86, 89 and 88%, respectively. It is concluded that the high diagnostic accuracy of immunoscintigraphy justifies a broader application of the scan in the diagnosis of infectious diseases. It is recommended that only late scans (20 h p.i.) are necessary.