Utility of galactomannan enzyme immunoassay and (1,3)beta-D-glucan assay in invasive fungal infection

Abstract

To evaluate the performance of the galactomannan enzyme immunoassay (GM test) and (1,3)beta-D-glucan assay (G test) for the diagnosis of invasive fungal infection (IFI). A retrospective study was performed in 115 hospitalized patients at Peking University First Hospital who were at risk of IFI. Patients were diagnosed as IFI according to revised definitions of invasive fungal disease from the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG) Consensus Group. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated at different cutoff values for two assays respectively. Two tests were combined to evaluate the changes of sensitivity, specificity, PPV and NPV. The best sensitivity (54.5%, 63.6%) and specificity (77.9%, 69.2%) were obtained with the cutoff values of 0.5 and 20 x 10(3) pg/L in GM test and G test respectively. The PPV were 20.7% and 17.9%, and the NPV were 94.2% and 94.7% respectively. The sensitivity increased to 90.9% and the specificity was 52.9% after a combined utility of two tests. The GM test and G tests are both useful in diagnosis of IFI with the cutoff values of 0.5 and 20 x 10(3) pg/L. A better sensitivity is acquired if there is a combined utility of two tests.