We evaluated the value of Aspergillus PCR as a tool for diagnosing invasive
aspergillosis from whole-blood samples during antifungal
therapy. In a 3-year study, 36 patients receiving antifungal
therapy due to chest radiographic findings highly suggestive of fungal
pneumonia were evaluated. The PCR results from whole-blood samples were compared to those obtained from bronchoalveolar lavage fluids and/or tissue specimens. A total of 205 whole-blood samples, 15 fine-needle aspirations or tissue biopsy specimens, and 21 bronchoalveolar lavage fluids and tracheal secretions were analyzed using PCR. Of the 36 patients, 15 had proven, 9 had probable, and 12 had possible invasive
Aspergillus infection according to European Organization for Research and Treatment of
Cancer/Mycosis Study Group definitions. For patients with proven
infection the sensitivity values of PCR in lung and blood samples were 100 and 40%, respectively. The negative predictive value of blood monitoring under conditions of antifungal treatment was 44%. Clearance of
fungal DNA from blood was associated with resolution of clinical symptoms in six of nine patients with proven
infection. Repeated positive PCR results for Aspergillus were associated with fatal outcome, as three of six patients died. For patients with probable
infection the sensitivity values of PCR in lung fluid and blood were 66 and 44%, respectively. The benefit of PCR diagnosis using whole-blood samples is limited when sampling takes place
after treatment has been started. Performance of Aspergillus PCR using tissue samples is recommended in addition to microscopic examination and culture technique for sensitive detection of
fungal infection.