(1-->3) Beta-D-glucan, or BDG, is a component of the cell wall of most fungi (not Zygomycetes or Cryptococcus though). Karageorgopoulos et al pooled 16 studies, including 2,979 patients with definite or likely fungal infections, that reported the test characteristics of serum BDG. The pooled sensitivity of serum BDG for invasive fungal infection was 77% and its specificity was 85%; however, statistical heterogeneity was high among the studies and most used the EORTC-MSG clinical criteria (not culture or histopathology for example) as their diagnostic gold standard for comparison. Clin Infect Dis 2011;52:750-770.