Current Challenges in the Diagnosis of Fungal Infections.

Diagnosing fungal infections is a challenge, particularly in the immunocompromised host. Signs and symptoms are nonspecific, colonization is difficult to distinguish from invasive disease, blood cultures are commonly negative, and patients are often unable to undergo invasive diagnostic procedures. Culture and microscopic examination remain the "gold standard" but are insensitive. Antigen assays such as the galactomannan and glucan detection systems are frequently used, yet these tests vary in sensitivity and specificity, depending on the patient population involved. Molecular-based assays are not yet clinically validated.