Background: Pleural effusion can be caused by various etiological conditions, commonest being tuberculosis. Histopathological examination, microbiological examination in addition with biochemical analysis of pleural fluid can help in determination of tuberculous pleural effusion. Estimation of Adenosine Deaminase (ADA) levels and lymphocyte / neutrophil ratio in the pleural fluid can help in the early diagnosis.

Material and methods: We studied 208 patients with pleural effusion. In our prospective study of 3 years we analyzed ADA levels along with lymphocyte/ neutrophil ratio in pleural fluid and total counts in the peripheral blood in both patients having tuberculous pleural effusion and non-tuberculous pleural effusion.

Results: Tuberculous pleural effusion cases showed the predominance in the lower age group when compared to non-tuberculous effusion cases. Both of them showed the male predominance. ADA levels in tuberculous pleural effusions ranged from 46.5IU/L to 210IU/L and non tuberculous pleural effusions ranged from 10.1IU/L to 48.4IU/L showing high ADA levels in tuberculous pleural effusions. Lymphocyte predominance was noted in tuberculous effusion where as neutrophil predominance was noted in non tuberculous effusion cases. There was no variability in the total count of leukocytes in peripheral smear.

Conclusion: Assessing ADA levels combined with lymphocyte/neutrophil ratio in the pleural fluid can increase the accuracy in diagnosing tuberculous pleural effusion.

Keywords: Tuberculosis; Pleural Effusion; Adenosine Deaminase; Lymphocyte Predominance.