The utility of galactomannan antigen in the bronchial washing and serum for diagnosing pulmonary aspergillosis

Abstract

The diagnosis of pulmonary aspergillosis is difficult because the sensitivity of the conventional methods for the detection of Aspergillus such as culture and cytology, is poor. To improve the sensitivity for Aspergillus detection, the detection of galactomannan antigen has been investigated. The serum galactomannan (GM) antigen has been recognized to be a useful tool for the diagnosis of invasive pulmonary aspergillosis. However, the utility of the galactomannan antigen for the diagnosis of pulmonary aspergillosis other than invasive pulmonary aspergillosis (IPA) has been unclear. The GM antigen using serum and bronchial washing (BW) using bronchofiberscopy for the diagnosis of pulmonary aspergillosis other than IPA were measured. In 45 enrolled patients, 7 patients had pulmonary aspergillosis, 5 of these patients had chronic necrotizing pulmonary aspergillosis and 2 patients had allergic bronchopulmonary aspergillosis. The area under the receiver operating characteristic (ROC) curve was 0.89 for the BW GM antigen detection test, and 0.41 for the serum GM antigen detection test, suggesting that the BW GM antigen detection test exhibits a better diagnostic performance than the serum GM antigen detection test. The BW GM antigen detection test had a sensitivity of 85.7% and a specificity of 76.3% at a cut-off level of ≥0.5, which was the optimal cut-off level obtained by the ROC curve. The BW GM antigen detection test is thought to be a promising test for the diagnosis of pulmonary aspergillosis other than IPA.