Diagnostic incremental value of sputum in patients with pleural tuberculosis

Background Pleural effusion (PE) Xpert has limited use in the diagnosis of pleural tuberculosis (TB). However, the diagnostic incremental value of sputum Xpert for pleural TB diagnosis remains unclear. Materials and methods Between March 2018 and October 2019, patients with certain causes (such as TB, malignancy, and pneumonia) of PE were enrolled in our study. Sputum and PE were collected from all patients and sent for acid-fast bacilli smear (Auramine O staining), mycobacterial culture (Lowenstein-Jensen media), and Xpert. The differences in the sensitivities of these TB assays between different groups were examined with the chi-square test. Results One hundred and twenty-seven PE patients were enrolled in the study and then were divided into pleural TB (n = 104) and other causes of PE (excluding TB, referred as non-pleural TB; n = 23). Compared with PE Xpert (11.5%, 12/104), sputum Xpert has a higher sensitivity of 25.0% (26/104, p = .012 < .05). The combination of sputum and PE has a non-significant higher sensitivity of 31.7% (33/104) than Xpert on sputum (p > .05). Culture using both sputum and PE combined has a high sensitivity of 43.3% (45/104). Conclusion Compared to PE Xpert, sputum Xpert showed an incremental diagnostic yield in the diagnosis of pleural TB and is expected to speed up the diagnosis of pleural TB.

Automated summary

In this study, we enrolled 127 patients with pleural effusion and found that sputum Xpert had a higher sensitivity in diagnosing pleural tuberculosis compared to pleural effusion Xpert. The combination of sputum and pleural effusion testing showed a higher sensitivity in diagnosing pleural tuberculosis.