The Performance of Quantitative Real-Time Polymerase Chain Reaction and Galactomannan for Invasive Fungal Infections in Patients with Hematologic Malignancies

Abstract

Background: Non-invasive methods to diagnose invasive fungal infections are needed to improve the poor outcome of these infections. We conducted this study to evaluate the diagnostic values of quantitative real time polymerase chain reaction and galactomannan in hematological malignancy patients. Results: Eighty-two consecutive patients with cancer were identified and prospectively followed for three months. Molecular testing using a quantitative polymerase chain reaction assay amplifying two primers 5.8S and 18S rRNA fungal genes and galactomannan was performed on 1540 blood samples and correlated with clinical data. Amplification of the 5.8S rRNA fungal gene had significantly higher sensitivity than amplification of the 18S rRNA gene for samples from either source (for blood samples: 90% vs 50%, p=0.007; for serum samples: 64% vs 5%, p<0.001). Conclusions: Galactomannan when used alone had a sensitivity of 38% and a specificity of 100%. The sensitivity of the combination assay of quantitative polymerase chain reaction plus galactomannan was significantly higher than that of GM test alone (71% vs 38%, p=0.03). Detection of the 5.8S rRNA fungal gene had significantly higher sensitivity than the 18S rRNA gene for samples from either source blood or serum. The combination of quantitative polymerase chain reaction plus galactomannan assay improved the diagnostic value of invasive fungal infections.