Diagnostic performance of metagenomic next-generation sequencing based on alveolar lavage fluid in unexplained lung shadows

Unexplained lung shadows are challenging in respiratory medicine, with both infectious and non-infectious etiologies. Lung biopsy is definitive but invasive, prompting a need for non-invasive alternatives. Metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid (BALF) is emerging as a promising diagnostic tool. We retrospectively analyzed 105 patients with unexplained lung shadows, collecting general information, mNGS results from BALF, and clinical diagnosis. We evaluated mNGS's diagnostic performance by comparing with final diagnosis. mNGS showed good diagnostic performance in differentiating infectious from non-infectious causes. The specificity and accuracy for bacteria and fungi exceeded 90%, while the sensitivity and precision for fungi were lower than for bacteria. Atypical pathogens were frequently identified, especially in mixed infections. mNGS of BALF is efficient in diagnosing infectious and non-infectious causes of unexplained lung shadows. While effective for bacteria and fungi detection, the sensitivity and precision for fungi are lower. [Abstract copyright: Copyright © 2024. Published by Elsevier Inc.]