Blood and BALF mNGS for viral detection. (a) The mNGS results for viral detection in 39 patients. 18 patients (black) had negative results in both blood and BALF mNGS. Viruses were detected in 21 patients, among whom 10 patients (purple) had positive results in both blood and BALF mNGS, 9 patients (red) had positive blood mNGS results, and 2 patients (green) had positive BALF mNGS results. The number of cases and percentage of different conditions are listed near the plot. (b) The distribution of pathogens identified by blood mNGS and BALF mNGS. Abbreviations: mNGS, metagenomic next-generation sequencing; BALF, bronchoalveolar lavage fluid; EBV, Epstein-Barr virus; CMV, Cytomegalovirus; HAdV, human adenovirus.