Objective To investigate the application value of bronchoalveolar lavage fluid(BALF)met-agenomic next-generation sequencing(mNGS)in elderly patients with severe pneumonia.Methods A total of 48 elderly patients with severe pneumonia admitted to the intensive care unit from January to August 2024 were selected and randomly divided into an observation group and a control group,with 24 patients in each group.BALF samples were collected within 24 hours of ICU admission from both groups,with lavage per-formed at the most radiologically evident lesion site.The control group underwent traditional culture at the hospital,while the observation group had one specimen sent for mNGS testing and another specimen subjected to traditional culture at the hospital.Comparison of detection results between mNGS and traditional culture in the observation group,pathogen distribution,infection markers(on days 4 and 7 of ICU admission),and prog-nostic outcomes were compared between the groups.Results The observation group showed higher positive detection rates and higher rates of detecting ≥2 pathogens by mNGS compared to both traditional culture in the same group and the control group(P＜0.05).Excluding Acinetobacter baumannii,Candida albicans,Can-dida glabrata,and Raoultella planticola,the observation group detected higher quantities of fungi,viruses,and rare pathogens than the control group.On days 4 and 7 of ICU admission,the observation group had signifi-cantly lower body temperature,white blood cell count,C reactive protein,and procalcitonin levels compared to the control group(P＜0.05).The observation group also demonstrated shorter ICU stays,reduced mechanical ventilation duration,and total lower hospitalization costs than the control group(P＜0.05).Conclusion BALF mNGS facilitates early identification of mixed and rare pathogens,improves detection rates,broadens microbial coverage,and shortens testing time.