Comparing the diagnostic value of targeted with metagenomic next-generation sequencing in immunocompromised patients with lower respiratory tract infection.

Background: Accurate identification of the etiology of lower respiratory tract infections (LRTI) is crucial, particularly for immunocompromised patients with more complex etiologies. The advent of next-generation sequencing (NGS) has enhanced the effectiveness of pathogen detection. However, assessments of the clinical diagnostic value of targeted NGS (tNGS) in immunocompromised patients with LRTI are limited.

Methods: To evaluate the diagnostic value of tNGS in immunocompromised patients with LRTI, a total of 88 patients, of whom 54 were immunocompromised, were enrolled. These patients underwent tNGS testing of bronchoalveolar lavage fluid (BALF). Results from both metagenomic next-generation sequencing (mNGS) and conventional microbiological tests (CMT) were also available for all participants. The performance of tNGS was assessed by comparing its findings against mNGS, CMT, and the clinical composite diagnosis.

Results: In the cohort of 88 patients, tNGS showed comparable diagnostic value to mNGS and was significantly superior to CMT. Compared to CMT and composite reference standard, tNGS showed sensitivity of 94.55% and 90.48%, respectively. In immunocompromised patients, despite a more diverse pathogen variety, tNGS maintained similar sensitivity to mNGS and outperformed CMT. tNGS positively influenced etiologic diagnosis and antibiotic decision-making in 72.72% of cases, leading to a change in antibiotic regimen in 17.05% of cases. We also compared the detection of microbial nucleic acids by tNGS with mNGS and found that tNGS could identify 87.99% of the microbial nucleic acids identified by mNGS.

Conclusion: In summary, our study demonstrated that tNGS offers promising clinical diagnostic accuracy in immunocompromised patients, as evidenced by its favorable comparison with CMT, the composite reference standard, and mNGS.