A prospective study of fungal biomarkers to improve management of invasive fungal diseases in a mixed specialty critical care unit

Purpose The diagnosis of invasive fungal diseases (IFD) in critical care patients (CrCP) is difficult. The study investigated the performance of a set of biomarkers for diagnosis of IFD in a mixed specialty critical care unit (CrCU). Methods A prospective observational study in patients receiving critical care for ≥ 7 days was performed. Serum samples were tested for the presence of: (1-3) - β-D-glucan (BDG), galactomannan (GM), and Aspergillus fumigatus DNA. GM antigen detection was also performed on bronchoalveolar lavage (BAL) samples. The patients were classified using published definitions for IFD and a diagnostic algorithm for invasive pulmonary aspergillosis. Performance parameters of the assays were determined. Results In patients with proven and probable IFD, the sensitivity, specificity, PPV and NPV of a single positive BDG were 63%, 83%, 65% and 83% respectively. Specificity increased to 86% with 2 consecutive positive results. The mean BDG value of patients with proven and probable IFD was significantly higher compared to those with fungal colonization and no IFD (p value < 0.0001). Conclusion New diagnostic criteria which incorporate these biomarkers, in particular BDG, and host factors unique to critical care patients should enhance diagnosis of IFD and positively impact antifungal stewardship programs.