 The survival of these patients depends on early diagnosis and prompt appropriate antifungal treatment. The early diagnosis of these infections is difficult because of the lack of sensitive test methods, notably blood cultures. For these reasons, the investigators decided to develop a real-time PCR Polymerase Chain Reaction assay on blood samples. It should allow rapid response to establish a positive or negative diagnosis of invasive fungal infection, could contribute strongly to the decision of treating using antifungals, and should monitor the effectiveness and the optimization of antifungal prescriptions. 