Diagnostic Value of Cross-priming Amplification Combined With CRISPR-Cas12b in Detecting Cell-free DNA in Tuberculous Pleural Effusion.

Background: Diagnosis of tuberculous pleural effusion (TPE) remains challenging. Studies have shown that detecting cell-free (cf-TB) DNA in pleural effusion can improve TPE diagnosis. This study aimed to evaluate the diagnostic value of our recently developed TB One-Pot assay, which combines cross-priming amplification with CRISPR-Cas12b, in detecting cf-TB for TPE.

Methods: Pleural effusion samples were collected from inpatients with suspected TPE at Hangzhou Red Cross Hospital. After centrifugation, the precipitate was used for culture, Xpert, and pleural effusion cytologic testing, while the supernatant was used for biochemical and cf-TB assays, including TB One-Pot and the quantitative polymerase chain reaction method (cf-TB-PCR). Assessment of diagnostic performance was based on a comprehensive reference standard.

Results: A total of 115 patients were included: 88 TPE cases (diagnosed per the comprehensive reference standard) and 27 non-TPE cases. The sensitivity of TB One-Pot in detecting pleural cf-TB for diagnosing TPE was 64.8%, with an area under the curve (AUC) of 0.805, significantly superior to culture and Xpert ( < .05). When compared with cf-TB-PCR (sensitivity, 53.4%; AUC, 0.767) and the adenosine deaminase assay (sensitivity, 52.3%; AUC, 0.761), TB One-Pot demonstrated slightly higher sensitivity and AUC, but the differences were not statistically significant ( > .05). The specificity of TB One-Pot was 96.3%, while the specificity of the other tests was 100%, with no statistically significant differences ( > .05).

Conclusions: cf-TB provides direct evidence of the etiology of TPE. TB One-Pot for detecting cf-TB in diagnosing TPE outperforms existing TB laboratory tests and may represent a more effective approach for TPE diagnosis in resource-limited settings.