This is a prospective, non randomized, non comparative study. Patients aged ≥ 18 years are eligible if they have acute leukemia, myelodysplasia or other baseline disease submitted to chemotherapy or to allogeneic stem cell transplantation with an expected duration of neutropenia (neutrophil count <500cells/mm³) of at least 10 days. Exclusion criteria are patients with and a past history of or invasive mold infection and those who do not want to participate. The study has no comparator arm. However, the investigators intend to determine if the algorithm based on the D-index would result in a 50% reduction in the use of antifungal agents, if all patients with persistent fever and neutropenia received empiric antifungal therapy. Based on our database of ~2,000 episodes of febrile neutropenia, 36% of patients had persistent fever between days 4 and 7 of antibiotics and would receive empiric antifungal therapy. A total of 105 patients will be needed to demonstrate a 50% reduction in antifungal use if the investigators compared this cohort with a matched control historical cohort (alpha = 5%, beta = 20%).