The diagnosis of invasive and noninvasive pulmonary aspergillosis by serum and bronchoalveolar lavage fluid galactomannan assay

Abstract

The incidence and mortality of invasive pulmonary aspergillosis (IPA) are rising, particularly in critically ill patients and patients with severe chronic obstructive pulmonary disease (COPD). Noninvasive aspergillosis occurring in these patients requires special attention because of the possibility of developing subsequent IPA, given the poor health and worsened immune state of these patients. We compared the performance of the Platelia galactomannan (GM) enzyme immunoassay in the bronchoalveolar lavage fluid (BALF) and serum. The sensitivity, and specificity of BALF-GM were 85.4% and 62.4%, and those of serum-GM were 67.9% and 93.5% at the cutoff index of 0.5. As the cutoff index increased, the specificity of BALF-GM detection was increased with the detriment of sensitivity. The area under the ROC curves was 0.817 (95% CI: 0.718-0.916) for BALF-GM and 0.819 (95% CI: 0.712-0.926) for serum-GM. The optimal cutoff index was 1.19 for BALF-GM, and the sensitivity and specificity were 67.9% and 89.2%. The BALF-GM assay is more sensitive in detecting pulmonary aspergillosis than serum-GM assay and fungal cultures. However, BALF-GM assay has a high false-positive rate at the cutoff index of 0.5. Hence, the diagnostic cutoff index of the BALF-GM assay should be improved to avoid the overdiagnosis of pulmonary aspergillosis in clinic.

Figure 1

The ROC curves of the BALF-GM and serum-GM assays for the diagnosis of invasive aspergillosis and noninvasive aspergillosis.