 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. Its sensitivity is poor or close-zero for aspergillosis. In addition, the response time is several days. For these reasons, we 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, it could contribute strongly to the decision of treating using antifungals, and it should monitor the effectiveness and the optimization of antifungal prescriptions. 