New perspectives in the diagnosis of systemic fungal infections.

Profound and prolonged neutropenia following chemotherapy is a major risk factor for systemic fungal infections. Mortality associated with disseminated fungal infection is high, and treatment with conventional amphotericin B is complicated by renal toxicity. Candida and Aspergillus are among the major pathogens in these patients. Many patients remaining neutropenic over a prolonged period of time will receive empirical antifungal therapy. The clinical and laboratory diagnoses of these infections are neither sensitive nor specific and are generally limited in the early detection of invasive fungal infection. However, several new approaches to diagnosis are being developed, which should be translated into routine practice, based on a greater understanding of the pathogenesis of systemic fungal infection and virulence determinants of fungal pathogens. These include antigen detection and polymerase chain reaction. Patients with presumed fungal infection require more intense and accurate monitoring for signs of disseminated infection. Early diagnosis may guide appropriate treatment and prevent mortality. Continued development of commercial tests should help achieve the objective of definitive diagnostic tests for systemic fungal infections.