THE DIAGNOSTIC VALUE OF PLEURAL EFFUSION Γ-INTERFERON RELEASE TEST AND ADENOSINE DEAMINASE ALONE AND IN COMBINATION FOR TUBERCULOUS PLEURISY

Guangjia Cheng¹, Fangli Mao¹, Keda Zheng¹, Lei Yuan¹, Jun Qin¹, Weiliang Kong^{2, *}

¹Department of Geriatric Respiratory, Fenghua People’s Hospital, Fenghua 315500, PR China - ²Department of Respiratory, Ningbo First Hospital, Ningbo 315000, PR China

Objective: To investigate the diagnostic value for tuberculous pleurisy of performing the interferon-γ release assay (IGRA) and adenosine deaminase (ADA) assay on pleural effusion, either alone or in combination. 

Methods: A total of 138 patients with exudative pleural effusion were admitted to the tuberculosis department of our hospital, from October 2018 to October 2019, and included in this study. According to the comprehensive clinical diagnosis, they were divided into a tuberculosis (TB) group (n = 92) and a non-tuberculosis group (n = 46). Within 24 hours of admission, 4 ml fasting venous blood was collected from all patients, and IGRA was performed after detection with an enzyme marker. During this period, 1 ml pleural effusion was collected from each patient, and ADA was assessed using a biochemical analyzer. 

Results: The IGRA-positive rates were 32.61% in the non-TB group and 83.70% in the TB group. The ADA-positive rates were 10.87% in the non-TB group and 30.43% in the TB group. The IGRA- and ADA-positive rates of patients in the TB group were significantly higher than those in the non-TB group (P<0.05). Both the IGRA index and the ADA assay have value for the diagnosis of TB pleurisy. The sensitivity of the IGRA index for the diagnosis of tuberculous pleurisy was 83.70%, the specificity was 67.39%, and the coincidence rate was 83.70%. For the diagnosis of TB pleurisy, the ADA assay had a sensitivity of 68.96%, a specificity of 91.30%, and a coincidence rate of 92.75%. Non-TB patients demonstrated a systemic positive test rate of 10.87%, and the systemic detection rate of TB patients was 65.22%. The positive parallel detection rate among TB patients was 36.96%, whereas the parallel detection rate among TB patients was 85.87%. Both the systemic and parallel detection rates for TB patients were significantly higher than those for the non-TB group (P<0.05). The sensitivity, specificity, and coincidence rate for the systematic detection and diagnosis of tuberculous pleurisy were 65.22%, 89.36%, and 73.91%, respectively. The sensitivity, specificity, and coincidence rate for the parallel detection of tuberculous pleurisy were 92.39%, 83.33%, and 82.60%, respectively. 

Conclusion: The positive IGRA and ADA rates in patients with tuberculous pleurisy were higher than those in patients with non-tuberculous pleurisy.