Use of real-time PCR on blood samples for diagnosis of invasive aspergillosis

We developed a new quantitative system for diagnosis of invasive pulmonary aspergillosis (IPA) using realtime automated polymerase chain reaction (PCR). Intra-assay and interassay precision rates for in vitro examination were 2.53% and 2.20%, respectively, and the linearity of this assay was obtained when there were > 20 copies/well. We examined 323 samples taken from 122 patients with hematological malignancies, including 33 patients with IPA and 89 control patients. Blood samples were subjected to PCR antigen detection methods, using enzyme-linked immunosorbent assay (ELISA) and determination of plasma (1-->3)-beta -D-glucan (BDG) concentration. The sensitivities of PCR, ELISA, and BDG measurement for diagnosis of IPA were 79%, 58%, and 67%, respectively; the specificities were 92%, 97%, and 84%. Positive findings on PCR preceded those of computed tomography by days, those of BDG measurement by days, and those of ELISA -0.3 +/- 6.6 by 2.8 +/- 4.1 days. Real-time PCR was sensitive for IPA diagnosis, and quantitation was accurate.