ABSTRACT

The diagnosis of invasive fungal infections (IFI) relies on the critical assessment of clinical presentation, associated risk factors, and careful interpretation of the appropriate diagnostic tests.  Frequently, clinicians have to initiate antifungal therapy based on their clinical suspicion and without having made a definitive diagnosis, particularly in cancer or other critically ill patients.  To complicate diagnosis, isolation of fungal organisms does not imply pathogenicity, especially from non-sterile sites, and may not necessitate treatment.  Hence, making the diagnosis of an IFI in clinical practice requires suspicion of disease, depends mostly on the acuity and severity of clinical signs and symptoms, and necessitates careful consideration of findings.  In this chapter we will review the traditional diagnostic modalities (culture, histopathology, and imaging) and recently developed diagnostic tools (BG, PCR, and GM EIA) for the diagnosis of IFIs.  This review will focus on the diagnosis of the most commonly identified IFIs in cancer patients, specifically invasive candidiasis (IC), invasive aspergillosis (IA), and zygomycosis.