Serodiagnosis of invasive aspergillosis in patients with hematologic malignancy: validation of the Aspergillus fumigatus antigen radioimmunoassay

Abstract

Six hundred sixteen sera from 79 hematology patients admitted on 152 occasions were analyzed for validation of the Aspergillus fumigatus antigen radioimmunoassay (RIA). Invasive aspergillosis developed on 24 admissions of 22 patients. Maximal antigenic activity was significantly higher in patients with invasive aspergillosis than in controls (P less than .0005). At the level of antigenic activity selected as the cutoff value, the sensitivity of the RIA was 74%, the specificity 90%, the positive predictive value 82%, and the negative predictive value 85%. Antigen was detected before invasive aspergillosis was suspected during 30% of admissions and before pathological or even preliminary microbiological evidence for disease in 46%. In 17 (77%) of the 22 episodes of pulmonary aspergillosis, the RIA would have been the first positive diagnostic test for aspergillosis or would have confirmed a diagnosis established by other means. Overall, the test would have been of clinical usefulness in diagnosis, management, and prognosis in 80% of 16 fatal cases.