Objective: To explore the relationship between the optical density index of serum aspergillus galactomannan (GM) assay and invasive aspergillosis (IA).
Methods: From Jan 2008 to Dec 2011, 825 hematological diseases patients with neutrophil count <0.5×10⁹/L⁹ by continuous blood count tests were admitted into our hospital. The optical density index of GM assay was ≥0.5 at least once. Of 825 patients, 247 cases were manifested as fever during hospitalization. The optical density index of GM antigen was detected by enzyme-linked immunosorbent assay, and the sensitivity and specificity of optical density ranged in 0.5-1.5.
Results: In this study, the sensitivity and specificity of GM assay with continuous twice samples (73% and 93%, respectively) were higher than single sample (66% and 80%, respectively) when optical density index ≥1.0. 69 cases were diagnosed as proven IA with the incidence rate of 8.36%.
Conclusion: The cut-off level for serum GM antigen assay should be decided as optical density index in two continuous samples of ≥1.0.