Abstract: Objective To investigate the diagnostic value of bronchial alveolar lavage fluid (BALF) metagenomic next-generation sequencing (mNGS) for pulmonary aspergillosis in the elderly patients. Methods A total of 190 patients with pulmonary aspergillosis were enrolled in this study, and were divided into the elderly group and the non-elderly group. The diagnostic value of traditional microbial culture, serum galactomannan antigen (GM) test, BALF GM test and BALF mNGS were investigated in the two groups. Results The positive rate of BALF mNGS was highest in the elderly group and the non-elderly group, followed by BALF GM test. There was significant difference in the positive rate of GM test between the two groups. Receiver operating characteristic (ROC) curve analysis showed that the diagnostic efficiency of BALF GM test was higher than that of serum GM test in the elderly group and the non-elderly group. The sensitivity and specificity of BALF GM test in the elderly group were higher than those in the non-elderly group.A total of 61 cases out of 99 elderly patients presenting with serum GM test less than 0.5 underwent BALF mNGS, and the positive rate of aspergillus was 80.3%. A total of 26 cases out of 28 elderly patients presenting with BALF GM test less than 0.8 underwent BALF mNGS, and the positive rate of aspergillus was 100%. Conclusions In the diagnosis of pulmonary aspergillosis in the elderly patients, the positive rate of BALF mNGS was higher than GM test and traditional microbial culture. Thus, BALF mNGS shows better diagnostic efficacy. In the elderly patients who are highly suspected of aspergillus infection despite the negative results of traditional microbial detection and GM test, BALF mNGS is an advantageous supplementary detection method.

Key words: pulmonary aspergillosis, galactomannan antigen test, bronchialalveolar lavage fluid, metagenomic next-generation sequencing