The differentiation of tuberculous effusion from the other causes of exudative pleural effusion remained difficult even with aids of biochemical analyses and pleural biopsy. As the pathophysiology of tuberculous pleural effusion is an enhanced cell mediated immunity, Adenosine deaminase(ADA) and various cytokines including Inteferon-γ, tumor necrosis factor alpha(TNF-α) are considered as useful diagnostic tools in differentiating exudative pleural effusion The author would like to demonstrate the diagnostic usefulness of TNF-α in the differentiation of exudative pleural effusion, and compared the discriminating ability of TNF-α with ADA.

Pleural fluids obtained from 80 patients (tuberculous : 39, malignant : 31, parapneumonic : 10) with exudate pleural effusions were processed for cell counts and biochemical analysis including ADA and TNF-α

Tuberculous pleural fluid showed higher levee of ADA and TNF-α, 48.7α 32.7U/L and 184.1±214.2pg/mL than that of non-tuberculous effusion 26.0α41.3U/L and 44.1α114.2pg/mL, respectively (ADA, TNF-α : p<0.05, p<0.01). Receiver operating characteristics(ROC) curves were generated for ADA and TNF-α, and the best cut-off value for adenosine deaminase and TNF-α were considered as 30U/L and 15pg/ml, respectively. Comparing the area under the ROC curves, there was no significant difference between ADA and TNF-α

For the differential diagnosis of tuberculous pleural effusion from the other causes of exudative pleural effusions, TNF-α as well as ADA was considered as useful diagnostic method. However adding TNF-α to ADA has no further diagnotic benefit than ADA alone.