An alternative to empiric antifungal therapy is the preemptive treatment. In this strategy, other markers (such as serology, radiology and clinical data) are added to persistent fever [5,6]. One problem of such strategy is that the biomarkers currently in use (galactomannan [GM], 1,3-beta-D-glucan and PCR) have high sensitivity. If one of these markers is used to trigger the start of antifungal therapy, still a considerable number of patients will use antifungal agents unnecessarily. However, a positive biomarker early in the course of neutropenia most likely represents a false-positive result. By contrast, a positive biomarker test late in the course of neutropenia is more likely to be a true positive. A problem is that no cutoff value of duration of neutropenia is validated to help clinicians to identify these 2 possibilities.