Detection of 1,3-β-d-glucan (BDG) in serum has been evaluated for its inclusion as a mycological criterion of invasive fungal infections (IFI) according to EORTC and Mycoses Study Group (MSG) definitions. BDG testing may be useful for the diagnosis of both invasive aspergillosis and invasive candidiasis, when interpreted in conjunction with other clinical/radiological signs and microbiological markers of IFI. However, its performance and utility vary according to patient population (hematologic cancer patients, solid-organ transplant recipients, intensive care unit patients) and pretest likelihood of IFI. The objectives of this article are to provide a systematic review of the performance of BDG testing and to assess recommendations for its use and interpretation in different clinical settings.