OBJECTIVE To explore the value of metagenomic next-generation sequencing technology (mNGS) in diagnosing infectious diseases by detecting cell-free DNA (cfDNA) in peripheral blood.

METHODS Peripheral blood mNGS, peripheral blood culture data and results of traditional etiological detection methods (fungal β-D-glucan test, GM test, X-pert, Rose Bengal plate test) were collected from patients who visited the People′s Hospital of Xinjiang Uygur Autonomous Region from Jul. 2022 to Jul. 2024 and underwent peripheral blood mNGS detection. Patients were divided into infected and non-infected groups based on their final clinical diagnosis. The diagnostic efficiency and result consistency of mNGS and traditional detection methods for infectious diseases were systematically compared.

RESULTS A total of 230 patients were included in this study, with 131 in the infected group and 99 in the non-infected group. The area under the curve (AUC) for the mNGS method was higher than that for blood culture and traditional etiological methods (0.666 vs. 0.580 vs. 0.619, respectively). Compared with blood culture, mNGS detection of peripheral blood cfDNA showed an additional pathogen detection rate of 62.60%, and compared with traditional pathogen detection methods, it showed an additional pathogen detection rate of 45.80%. The result consistency between mNGS detection of peripheral blood cfDNA and blood culture detection was poor (Kappa=0.266, P < 0.001). mNGS was used to detect peripheral blood cfDNA, and Coxiella burnetii, Chlamydia psittaci and Mycobacterium tuberculosis complex were detected.

CONCLUSIONS The use of mNGS to detect peripheral blood cfDNA demonstrates significantly superior diagnostic efficiency and detection coverage for infectious diseases compared to blood culture and traditional etiological detection methods. It exhibits significant advantages in the diagnosis of infectious diseases and can serve as an effective detection method for clinically identifying special pathogens and occult infections.