Performance of Fungitell STAT point-of-care test for the diagnosis of invasive fungal diseases

Abstract

(1→3)-ß-d-glucans (BDG), major cell wall components of most pathogenic fungi, are useful for the diagnosis of invasive fungal diseases (IFD) due to their high negative predictive value. For several years, a number of BDG detection tests are commercially available, including Fungitell Assay (FA) and Wako assay, and more recently Fungitell STAT (STAT) unit test. Our aim was to compare the performance of the two Fungitell assays for IFD diagnosis. Sera from 90 patients with Pneumocystis jirovecii pneumonia (PJP, n = 30), candidemia (n = 30), and invasive pulmonary aspergillosis (IPA, n = 30), 30 patients colonized by P. jirovecii, and 70 healthy controls (women followed-up during pregnancy) were analyzed retrospectively. STAT and FA assays were performed according to manufacturer's instructions. The overall level of agreement between two Fungitell assays was excellent (weighted Cohen's kappa = 0.87 [95% CI: 0.80-0.94]). BDG rates were significantly higher in candidemia, IPA and PJP than in healthy controls (P < .0001). BDG rates were also significantly higher in PJP than for P. jirovecii colonization (P < .0001). Area Under the Curve (AUC) of STAT (0.92) was higher than FA (0.86) for IFD diagnosis. Using optimized positivity thresholds for IFD diagnosis (94 pg/ml and 0.86 for FA and STAT, respectively), sensitivities and specificities were 78.9% and 90% for FA and 85.6% and 88.6% for STAT, respectively. AUC of FA and STAT were higher for PJP diagnosis than for candidemia and IPA diagnosis. Compared to FA, STAT assay represents an interesting option for emergency IFD diagnosis and for small care centers.

Keywords: (1→3)-ß-d-glucans; Fungitell Assay; Fungitell STAT; invasive fungal diseases.