Galactomannan in the bronchoalveolar lavage for diagnosing invasive fungal disease

Invasive fungal disease (IFD) is a significant cause of morbidity and mortality in immunocompromised patients. We hypothesize that galactomannan, a component of fungal cell wall, as measured in the bronchoalveolar lavage (BAL GM) might be a diagnostic adjunct in hematological malignancies. 568 hematological patients undergoing diagnostic bronchoscopy due to respiratory symptoms and/or suspected IFD between 2009 and 2013 at a tertiary care center in Switzerland were included in this prospective, observational cohort study. We compared accuracy of the BAL GM ELISA determination in predicting IFD as classified by the EORTC/NIAID definition. BAL-GM was positive in 155 cases (29.2%). According to the EORTC/NIAID criteria, IFD was classified as possible in 183 (34.5%) and potential in 50 (9.4%) cases (6 proven; 44 probable). BAL GM provided 50% sensitivity, 73.0% specificity, 16.1% PPV, 93.4% NPV, 1.86 PLR and 0.68 NLR for potential IFD; corresponding values for proven IFD were 50%, 71.2%, 2%, 99.2%, 1.73 and 0.70. The AUC of the ROC curve for the diagnosis of potential IFD was 0.716 (95%CI 0.638-0.794, p<0.001). Galactomannan in the bronchoalveolar fluid has a modest accuracy and thus limited clinical usefulness for diagnosing invasive fungal disease in immunocompromised patients.