Accuracy of plasma cell-free DNA PCR for non-invasive diagnosis of mucormycosis.

Diagnosis of mucormycosis poses a substantial challenge due to the lack of a non-invasive biomarker and limitations of conventional diagnostics using invasive specimens. The aim of this study was to characterize the performance of Mucorales plasma cell-free DNA (cfDNA) PCR in immunosuppressed and non-immunosuppressed patients with pulmonary, disseminated, and localized mucormycosis. Patients with Mucorales plasma cfDNA test results were retrospectively categorized as proven or probable for sensitivity analysis and as no Mucorales infection for specificity analysis. In total, 85 positive and 212 negative Mucorales plasma cfDNA test results in unique patients were included in this study. Per the expert definitions, 47 patients had proven or probable mucormycosis, and 171 did not have invasive Mucorales infection. The Mucorales plasma cfDNA PCR had an overall sensitivity and specificity of 85.1% (40/47, 95% CI, 71.7-93.8) and 92.9% (158/170, 95% CI, 88.0-96.3), respectively. The sensitivity was 92.1% (35/38, 95% CI, 78.6-98.3) and 55.6% (5/9, 95% CI, 21.2-86.3) in patients with and without immunosuppression, respectively, and 100% (14/14, 95% CI, 76.8-100), 89.5% (17/19, 95% CI, 66.9-98.7), and 64.3% (9/14, 95% CI, 35.1-87.2) in patients with disseminated, pulmonary, and localized mucormycosis, respectively. Mucorales plasma cfDNA PCR is a sensitive and specific non-invasive testing modality for the diagnosis of mucormycosis in immunosuppressed patients and those with pulmonary and disseminated infection.IMPORTANCEMucormycosis is an invasive mold infection associated with high morbidity and mortality. Early diagnosis and effective antifungal treatment are critical for improving clinical outcomes. However, diagnosis of mucormycosis is often delayed due to the lack of a non-invasive biomarker and insensitivity of culture and non-specificity of histopathology performed on invasive specimens. Mucorales plasma cell-free DNA (cfDNA) PCR is a novel testing modality that allows non-invasive diagnosis of mucormycosis. In the current study, we evaluated the clinical performance of a pre-analytically optimized Mucorales plasma cfDNA PCR in immunosuppressed and non-immunosuppressed patients with pulmonary, disseminated, and localized infections. We show that Mucorales plasma cfDNA PCR is highly sensitive and specific in immunosuppressed patients with pulmonary and disseminated infections. Thus, the Mucorales plasma cfDNA PCR represents an accurate diagnostic tool for non-invasive diagnosis of mucormycosis, which may enable early treatment and improved outcomes in immunosuppressed patients with mucormycosis.