Galactomannan detection in computerized tomography-based broncho-alveolar lavage fluid and serum in haematological patients at risk for invasive pulmonary aspergillosis

We determined the value of galactomannan (GM) detection in computerized tomography (CT)-based broncho-alveolar lavage (BAL) fluid and serum for the diagnosis of invasive pulmonary aspergillosis (IPA) in haemato-oncological patients with neutropenia. CT of the thorax and BAL were performed systematically at predefined clinical indications. GM was determined by sandwich enzyme-linked immunosorbent assay; the clinicians were unaware of the results. Of 160 patients, 17 patients (10.6%) presented with proven, probable or suspected IPA. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of GM detection in CT-based BAL fluid were all 100%. For GM detection in serially sampled serum, the sensitivity was 47%, the specificity 93%, the PPV 73% and the NPV 82%. A non-blinded follow-up study was performed to validate these results. In this study, 22 of 198 patients (11.1%) presented with IPA, and the sensitivity, specificity, PPV and NPV of GM detection in CT-based BAL fluid were 85%, 100%, 100% and 88% respectively. None of BAL fluids obtained after antifungal treatment of 3 d or more were positive. These results indicate that, when CT is used systematically and at an early stage, GM detection in CT-based BAL fluid has a high PPV for diagnosing IPA early in untreated patients.