Background: Pleural effusion is a common medical condition with many possible underlying etiologies. However, Tuberculosis is the most common cause of pleural effusion especially in countries like Nepal. Pleural fluid lymphocytosis is seen in tuberculosis, malignancy and few auto-immune diseases. Adenosine Deaminase activity (ADA) level in tubercular pleural effusion is markedly increased compared to non-tubercular effusions. ADA estimation being a simple colorimetric method is suitable for the rapid diagnosis of tubercular effusion. This study aims to correlate the diagnostic efficacy of ADA with the value of differential count (lymphocytosis) in establishing different etiology of pleural effusion.

 

Materials and methods: This is a cross sectional study of 50 cases with pleural effusion carried out in the department of Pathology, Green city hospital for the duration of Twenty one month’s dating from October 2014 to July 2016 AD.

Result: Of all, tubercular pleural effusion accounted for 26%.  ADA level was raised (40U/L) in 92% of Tubercular pleural effusion.  The sensitivity and specificity of ADA alone to diagnose tubercular pleural effusion was 92% each and when lymphocytosis alone was considered sensitivity was 85% with specificity of 32% whereas the combined effect of both  ADA with lymphocytosis was 100% (sensitivity) and 87% (specificity), 83% (positive predictive value) and 100% (negative predictive value) respectively with statistically significant p value (<0.05).

Conclusion: We can conclude that the combination of pleural fluid differential count (lymphocytosis >50%) and ADA level >40U/L provides with much more positive result than each component alone in differentiating tubercular effusion from other etiologies.

Key words: Tuberculosis, pleural effusion, Adenosine Deaminase, Lymphocytosis, pleural fluid