(1-3)-β-D-Glucan vs Galactomannan antigen in diagnosing invasive fungal infections (IFIs)

Invasive fungal infections (IFIs) are serious and often life-threatening complications in patients with haematological malignancies. Early diagnosis and the initiation of efficacious antifungal treatments could affect the prognosis of these patients. The detection of (1-3)-β-D-Glucan (BDG) could be a promising non-culture-based, noninvasive tool for IFI analyses in haemato-oncological patients, allowing the diagnosis of the two major IFIs, invasive aspergillosis (IA) and invasive candidiasis (IC), with a single test. The aim of this work was to evaluate and compare the use of the BDG in combination with the galactomannan antigen (GAL) assay in order to exclude or confirm suspected IFIs. Sera from 46 haemato-oncological patients (24 with proven/probable IFI and 22 without IFI symptoms) were evaluated retrospectively for the detection of GAL and BDG. In 24 patients, the serum BDG levels facilitated IFI diagnosis: 18 probable IA, 3 proven IA and 3 IC. In the remaining 22 patients, the BDG level helped exclude IFIs. The BDG was positive earlier than GAL in 5/24 cases [three of probable invasive aspergillosis (IA), one of proven IA and one case of proven invasive candidiasis (IC)] and was positive at the same time as GAL in 19/24 cases; in no case was GAL positive before BDG was. The BDG detection is useful, however, the test has a great limitation because it is a completely manual procedure.