Application of adenosine deaminase combined with γ-interferon release test in the diagnosis of tuberculous pleural effusion in patients over 40 years old

Abstract Background: The diagnostic accuracy of pleural biomarkers in patients with tuberculous pleural effusion (TPE) of different ages is inconsistent, but specific studies in different age groups are lacking. Therefore, we investigated the cut-off value of adenosine deaminase (ADA) and its combined gamma interferon release assay (IGRA) in the diagnosis of TBE patients of different ages in aged≥40 years. Methods: A retrospective analysis of 176 patients who were hospitalized from 2015 to 2020 and had pleural effusion with or without fever,night sweats, fatigue,cough and other clinical manifestations and were highly suspected of tuberculous pleural effusion. The results of medical thoracoscopy and pleural effusion ADA and IGRA were analyzed. The patients were divided into 40-59-year-old group and≥60-year-old group. Results: Among the 176 patients, 85 were aged 40-59 years, and 91 were aged≥60 years. The cut-off value of ADA in ROC analysis is 31.5 U/L, the accuracy is higher than 40 U/L (85.80%vs.82.95%), but the diagnostic sensitivity in patients aged≥60 years is lower than that in the group of 40-59 years old (71%vs.83%).The sensitivity of IGRA detection in patients aged≥60 years was higher than that of ADA (93% vs.71%). The detection sensitivity of ADA combined with IGRA in pleural effusion was the highest in the 40-59-year-old group, reaching 100%. The specificity of ADA united IGRA detection in pleural effusion was the highest in the age≥60 years group, reaching 100%. Conclusions: The detection of ADA and IGRA in pleural effusion has good diagnostic value for patients with suspected TBE aged≥40 years. ADA unites IGRA detection is beneficial to the detection rate of TBE in patients with exudative pleural effusion aged 40-59 years, and it is beneficial to the differential diagnosis of TBE in patients aged≥60 years.