Diagnosis of invasive fungal infections by a real-time panfungal PCR assay in immunocompromised pediatric patients

Invasive fungal disease (IFD) is a life-threatening event in immunocompromised patients, and there is an urgent need for reliable screening methods facilitating rapid and broad detection of pathogenic fungi. We have established a two-reaction real-time PCR assay permitting highly sensitive detection of more than 80 fungal pathogens, covering a large spectrum of moulds, yeasts and Zygomycetes. To assess the clinical potential of the assay, more than 600 consecutive specimens from 125 pediatric patients carrying a high risk of IFD were analyzed. An excellent correlation between PCR positivity and the presence of proven, probable or possible fungal infection according to the European Organization for Research and Treatment of Cancer criteria was demonstrated, as revealed by the sensitivity of the assay of 96% (95% CI: 82-99%). The negative predictive value of the panfungal PCR assay presented was 98% (95% CI: 90-100%), while the specificity and the positive predictive value were 77% (95% CI: 66-85%) and 62% (95% CI: 47-75%), respectively. The results indicate that molecular screening of patients during febrile neutropenic episodes by the assay presented could help prevent unnecessary toxicity resulting from empirical antifungal treatment in individuals who may not be at risk of imminent fungal disease. Our observations raise the possibility that rapid species identification may be required to increase the positive predictive value for impending fungus-related disease.